Hey, I haven't driven a TEC yet but im planning on doing so in my next build.
After a quick google search i managed to find this
http://smtzone.com/mm5/merchant.mvc
They have TEC drivers, modules and all sorts of interesting things. It may not be the cheapest but its probably (probably) quality stuff hence the price.
If you are looking for cheaper stuff i would try Ebay or Aliexpress.
-Hybrid
1x - 2W RGB DT40Pro (Currently building)
1x - 1W RGB PT25K
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EtherDream, LaserShowExpress, Ipad (TouchOSC)
-Hybridz0rz