Signature solar has a rack mount 12v 400Ah for $1,500 on preorder. I got mine in 2 weeks, not the 8-10 that they're saying. These are the EG4-LL ones Will has been raving about lately.
Walmart has the Zooms 12v 100Ah for $309 +free shipping. This is a Chins clone, so no low temp unfortunately.