Just got the UTStarcom OEM 1900mah extended battery and back for the wife's touch
http://www.wirelessground.com/htcbte6900spb.html (not where I got it, bought it off a fellow PPCgeeker)
The back fit is perfect, adds a bit of heft but it's actually nice for those of us who find the stock touch to be almost too thin and light
The extra capacity is sure welcome! Standby all day with just email checks it was still at 92% Looks like a winner.