OK, finally tested GXMame. It works; I had to make a dummy xmame package using equivs and then copy the maemo XMame.SDL into Debian /usr/games and make an xmame softlink; I also had to copy the libXsp.0.1.0 file and make a softlink for it (there doesn't seem to be a package "libxsp0" in Debian). Perhaps you could make a package for that library too? I then had to set up all the directories in GXMame, because it claims to have no idea where the executable is.