MAME Light Guns - What's the MAME Cabinet?

Linux light guns are something that have always got me a little bit excited. How do they work on flat screen TVs or monitors? Do you know? I would guess that they probably emulate kind of mouse input or something, and you've got to find a device that translates it into motion like a Wii controller. It wouldn't surprise me if somebody's got the original light gun things working with some pretend input scan line. MAME always surprises me that the quality of the emulation is second to none. Even things like old 8-bit home computers seem to be emulated better in MAME than they are elsewhere.