What's your problem with MAME ?
Is KI too heavy to run on the ipad, or are you simply not making it work ?
I took this from "fantasyanime.com" in case you don't know how to do with chd files:
Loading a CHD (hard drive) game
Arcade games based on a hard drive require some extra steps. You need two things: (1) the parent ROM, and (2) the CHD file (the hard drive file). The size of the parent ROM is tiny, but expect the CHD file to be around 100 MB. So to get 'em to work, I'll use Killer Instinct as an example:
1. The parent ROM for Killer Instinct is “kinst.zip” and the CHD file is “kinst.chd”. Place “kinst.zip” into the 'roms' folder as you would with any other MAME ROM.
2. Within the 'roms' folder, create a new folder and call it kinst (the exact name of the ROM).
3. Move “kinst.chd” over to this new kinst folder.
4. Open MameUI and press F5 to refresh the ROM list. You should see Killer Instinct come up in the Available list. Double-click to play