I have bought 1800 mAh Chinese battery, 1750 mAh Seidio battery and 2200 Chinese battery... don't really give you much of a battery charge. Sure, they fit, but after constant charging... I went with the Chinese battery 3000 mAh for $9.99.
Fat back door? It gives it a better grip. Well if you have a big hand... otherwise you should have gotten the Hero. It really doesn't make it look too "fat". The Chinese backdoor snaps out snugly. It fits on my Seidio holster and my Evo dock. Feels more sturdy.
Recently bought a Chinese battery 3500 mAh battery with back door for $10- hardly "over priced" it costs just as much as the 2200 mAh battery you want... Except, I would advise to forget the Seidio battery- now those are over priced!
With my 3500 mAh battery I have gotten 32 hours of average use without charging. Worth my "over priced" $10!