I have had no luck with any accessories.

1. Bought a SENA pouch case for $30 but it doesn't fit. It fits the GSM model with smaller depth. You can get the Sprint version in the case but it is too tight. The GSM model is 4x2x.5 in, whereas the Sprint CDMA version is .1 in bigger(or 2.5 mm) at 4x2x.6 in. Sent the case back.

2. Bought a OEM Sprint CDMA baterry from igonemobile.com for $25. Was DOA and a tight fit for the charger. The new battery was supposed to be 1345 ma. GSM 900 ma battery works, but phone can't read it. Use in emergency. Trying to send battery back to igonemobile.

3. Bought HTC diamond styli from Xpansys for $17 in black,couldn't find the Sprint burgundy. GEB diamond back styli are different, not magnetic and do not fit the Sprint CDMA version. They work but makes the stylus end stick out. Am sending styli back.
Did have luck with charger base from Daydeal - works with phone, comes with an AC adaptor.
Sprint says they have stylus @ $19 each and battery at $39.