Here's a few suggestions, if you get the time:
- Zip decompression built in
- Ability to specify ROMs directory
One great advantage to MAME32 for the desktop is the ability to dump dozens (I have 114) roms in their own ZIP file, keeping them very organized (you don't have to unzip all 1000+ files to play the games). This would also help people like me that try to cram just 4 or 5 games on the handheld cause I don't have enough ram (HP 548 32mb w/8meg 'free' card. 128mb ONE day.. soon maybe).
The other feature of the ability to specify the directory of the ROMS would help as I plan on storing my ROMs on one flash card, and MP3s on the other.