There is a HPC 2000 version of MameCE, supports this kind of devices like Jornada 720. However you can use it on any pocketPC without problems. I use it on my Cassiopeia e-125 i'm able to play Robocopp, Rastan, Prehistoric Island and many more wich requiers M68k emulation. They play nearly full speed so you can expect perfect gameplay on newer pdas.
There is however a backdraw on this, you need some kind of program for assigning PAD hard keys to standard HPC keyboard. I have an utility called palmkeys by conduits software but that's for mips.I dunno if something similar actually exists for Arm CPu's but is worth the check.
Install the emu from .cabs avaiable form the page and tell me your results.

Here are the links:

http://randy3.hp.infoseek.co.jp/mobile/
http://randy3.hp.infoseek.co.jp/mobile/Readme.txt

Good luck!!!