The 1860 election returns can be obtained on micro-film from the Texas State Archives in Austin. I live far away and do not currently have the time, but you can get an inter-library loan. The records are on Reel EX-5. http://www.tsl.state.tx.us/arc/exrecordsbks.html
As an aside note, there must have been a higher percentage of slaveowners in Texas than elsewhere. That would make sense to me because the Republic was established primarily by slave holding Southern immigrants. Some may have been appropriately considered invaders by the pre-Republic Mexican government In 1860, one in four families (the majority lived in East Texas) were slave owners. Five branches of my mother's family immigrated to Texas between 1830 and 1842. 4/5's were slave owners. One of the families owned over 30 slaves in 1860, but most of my mother's ancestors no longer owned any slaves.