I especially recommend these articles from Mormons...though the seventh is not Christmas specific:
* The Joseph Smith Crèche at BYU, December 2005 [Mormon Merry Smithmas!]
* Dealing with Smithmas [Mormon worship of Joseph Smith]
* Praise To The Man: A Review Of The Annual Joseph Smith Memorial Sermons [Mormon Merry Smithmas]
* Joseph Smith: a witness of Christ [O Come, O Come EmmanSMITHuel, anyone?]
* A Prophets Life: The CradleSharon, Vermont [Mormon Merry Smithmas Day!]
* The dreaded Christmastime ward sacrament meeting [Mormon Merry Smithmas!]
* Praising the man [Mormon Merry Smithmas!]
These other recent threads provide additional evidence:
* Reasons Joseph Smith Is More Important Than Jesus [Mormon Merry Smithmas!]
* 'Praise to the Man' honors Joseph Smith [Mormon Merry Smithmas!]
* Joseph Smith: Blessed Be His Name [Mormon Merry Smithmas]
* Joseph Smith Jr.Prophet of God, Mighty Servant
* Tis the season for Smithmas; Whom do you worship? [Mormon Merry Smithmas]
I thought Jesus was born in the Summer.
The Mass of Christ was set in December to replace the pagan celebration, Saturnalia, successfully.
Just something I heard.