Yeah, I don't think you'd find to many buyers. There are a lot of Evo 4g's on craigslist right now though.
This is what I did to make my extended battery work with an otterbox case. Although I wasn't to big on it since the rubber would never stay in place around the screen.
HTC EVO 4G w/ HTC 2150 Battery and Otterbox Defender
Nexus 5 - SlimKat : OnePlus One Paranoid Android
Samsung Galaxy Nexus - Sold ; Nexus S4G -Broken
HTC Evo 4G LTE Black (Sold) & White - (Sold)
Evo 4G - Sold
Nexus 7 - SlimKat