I bought this "cheap " battery.
http://cgi.ebay.com/ws/eBayISAPI.dll...0%3D%26fvi%3D1
I didn't think the door would fit, but it fits perfectly. I ordered the OEM Touch extended door which looks nicer and has the rubbery coating.
Had it 2 days and so far it stil has about 20% left at the end of a day of consistent usage,surfing,music,streaming. Normally my stock battery would go dead about 4:00 in the afternoon!