Phew! Kamenraider pointed me to some humdingers! I bolded the best ones...
" 'Well, sister Pratt,' says Joe, 'as you have refused me, it becomes sin, unless sacrifice is offered:' and turning to me he said, 'General, if you are my friend I wish you to procure a lamb, and have it slain, and sprinkle the door posts and the gate with its blood, and take the kidneys and the entrails and offer them upon an altar of twelve stones that have not been touched with a hammer, as a burnt offering, and it will save me and my priesthood. Will you do it? 'I will,' I replied. So I procured the lamb from Capt. John T. Barnett, and it was slain by Lieut. Stephen H. Goddard, and I offered the kidneys and entrails in sacrifice for Joe as desired; and Joe said, 'all is now safe -- the destroying angel will pass over, without harming any of us.' "
--John C. Bennett letter to Simeon Francis, editor of the Sangamo Journal, July 5, 1842, (see Wasp Extra, July 27, 1842; Sangamo Journal, July 15, 1842) quoted in Cultures in Conflict by John E. Hallwas and Roger D. Launius, Logan UT: USU Press, 1995, pg. 119.
The Scripture in D&C 84:20-31 reads:
Therefore, as I said concerning the sons of Moses-for the the sons of Moses and also the sons of Aaron shall offer an acceptable offering and sacrifice in the house of the Lord, which house shall be built unto the Lord in this generation, upon the consecrated spot as I have appointed.
And D&C 13:1 reads:
Upon you my fellow servants, in the name of messiah I confer the Priesthood of Aaron, which holds the keys of the ministering of angels, and of the gospel of repentance, and of baptism by immersion for the remission of sings; and this shall never be taken again from the earth until the sons of Levi do offer again an offering unto the Lord in righteousness.
D&C 128: 24 reads:
Behold the great day of the Lord is at hand...he shall purify the sons of Levi and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness. Let us, therefore, as a church and a people, and as Latterday Saints, offer unto the Lord an offering in righteousness; and let us present in his holy temple; when it is finished, a book containing the records of our dead, which shall be worthy of all acception.
Another Brigham Young quote:
"When we see a temple built right, there will be a place for the priests to enter and put on their robes, and offer up sacrifices, first for themselves, and then for the people."
--Heber C. Kimball Journal, January 2, 1846, see BYU Studies, Spring 76, Vol. 16 #3, pg. 384.
Oliver B. Huntington had this to say:
"I heard the Prophet [Joseph Smith] reply to the question: 'Will there ever be any more offering of sheep and heifers and bullocks upon altars, as used to be required of Israel?'
He said: 'Yes, there will, for there were never any rites, ordinances or laws in the priesthood of any gospel dispensation on this earth but what will have to be finished and perfected in this the last dispensation of time -- the dispensation of all dispensations.' "
--They Knew the Prophet, by Hyrum L. & Helen Mae Andrus, SLC: Bookcraft, 1974, pg. 62.
This one is from Wandle Mace:
"The Quorum of the Twelve had been filled, but of the number selected one--Willard Richards--was in England and Joseph was instructing those present of that Quorum how they must proceed to prepare themselves, that they might ordain Willard Richards to the Apostleship when they should reach that country. Joseph told them to go to Kirtland and cleanse and purify a certain room in the temple, that they must kill a lamb and offer a sacrifice unto the Lord which should prepare them to ordain Willard Richard a member of the Quorum of the Twelve Apostles.
Sidney made some remarks, when Joseph spoke with great power and spirit, said he, 'I know the law'. To a remark made by Heber C. Kimball he said, 'It will be the sweetest smelling savor you ever smelled.' "
--Journal of Wandle Mace, typescript, Harold B. Lee Library, BYU, pg. 32.
D&C 124:39 Therefore, verily I say unto you, that your anointings, and your washings, and your baptisms for the dead, and your solemn assemblies, and your memorials for your sacrifices by the sons of Levi, and for your oracles in your most holy places wherein you receive conversations, and your statutes and judgments, for the beginning of the revelations and foundation of Zion, and for the glory, honor, and endowment of all her municipals, are ordained by the ordinance of my holy house, which my people are always commanded to build unto my holy name.
Here's another quote from Wilford Woodfuff's Journal, March 23, 1837:
"Immediately after entering the house [Kirtland Temple] in company with several other Elders, I went within the veil and we bowed down before the Lord in the Aaronic [priesthood] stand and offered a morning sacrifice and the Spirit of God rested upon us with joy to our souls... ."
Here's what the First Presidency (Heber J. Grant, Anthony W. Ivins, and J. Reuben clark, Jr.) had to say:
"The members of the Church are reminded that the practice of polygamous or plural marriage is not the only law whose suspension has been authorized by the Lord and adopted by the people. The law of animal sacrifice, in force in ancient Israel, has been suspended, but the Prophet Joseph asserted it would be again restored, and such is the effect of the statement made by John the Baptist when restoring the Aaronic priesthood. The law of the United Order has likewise been suspended, to be reestablished in the due time of the Lord. Other laws might be mentioned."
--Messages of the First Presidency 5:327
Sidney B. Sperry wrote:
"The First Presidency of the Church once assured me in writing, through a member of the Twelve (in 1921 or 1922 as I remember), that they concurred with the Prophet's words on this point, [the continuation of animal sacrifice in the last days 'from generation to generation' TPJS p. 172] but added that in their opinion sacrifice would be on a more limited scale than formerly."
--Doctrine and Covenants Compendium, SLC: Bookcraft, 1960, pg. 394.
In Joseph Smith's journal for April 2, 1843 (see An American Prophet's Record, ed. by Faulring) we find: "...the 144,000 sealed are the priests who are appointed to administer in the daily sacrifice."
There's an 1845 quote from Zina Diantha Huntington Jacobs (from BYU Studies, Spring 79, V. 19, No. 3, pg. 302) where she describes how an Elder Dunham "spoke of the nations sending up their bullocks for sacrifices or have no rain..." which is an allusion to this Bible passage about life during the millenium:
Zechariah 14:16-21
16 And it shall come to pass, that every one that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the LORD of hosts, and to keep the feast of tabernacles.
17 And it shall be, that whoso will not come up of all the families of the earth unto Jerusalem to worship the King, the LORD of hosts, even upon them shall be no rain.
18 And if the family of Egypt go not up, and come not, that have no rain; there shall be the plague, wherewith the LORD will smite the heathen that come not up to keep the feast of tabernacles.
19 This shall be the punishment of Egypt, and the punishment of all nations that come not up to keep the feast of tabernacles.
20 In that day shall there be upon the bells of the horses, HOLINESS UNTO THE LORD; and the pots in the LORD's house shall be like the bowls before the altar.
21 Yea, every pot in Jerusalem and in Judah shall be holiness unto the LORD of hosts: and all they that sacrifice shall come and take of them, and seethe therein: and in that day there shall be no more the Canaanite in the house of the LORD of hosts.
-CK