You can also install a wireless network card and use Remote Desktop from another PC. No mess, no cables, no hassle and no extra work 
Agreed. The tools are more than good enough now to make this a legitimate method for accessing the operating system.
Admittedly I'm snobby in this regard; I'm a purist, though often this is an impractical position, and I know that. However, I see no valid reason whatsoever for this logic, which I see demonstrated day in and day out on this board: "I love arcade games! I'm going to change
everything about them when I build mine!"
It's never actually spelled out like that, but then people go and build cabinets with PC monitors or with the monitor at the wrong angle or position, or they add really weird things like keyboard drawers, or coat hangers (saw that more than once) or convertible cabinets, or what one of the worst and most common: every single input method on a single control panel. Dual 8-way, dual 4-way, dual trackball, dual spinner, 12 buttons per player, etc. ZERO NEED... ZERO NEED.
The old games were so great precisely because they were single purpose machines. I'm not saying that you should have 24,000 cabinets because you have 24,000 roms, I'm saying that you should really look closely at what you actually need, and be practical about implementing it.
Ideally, for emulation, I'd have a DOS-based PC that I could boot to USB, and autoexec.bat would have "mame mspacman" (or whatever game I felt like playing that week) and that would be that. I wouldn't have a menu, there would be no quick and easy way to change the game (shut off, swap thumb drive, turn on isn't that bad, but menus are too easy.)
I get off on this tangent way too much. My point is: what are you doing to your emulator PC that you need to access it at all, outside of the control panel? Let it emulate and leave it alone. If you have a single PC doing file serving and emulation, well, that PC is doing 1 too many things. That's my stupid opinion, and I'm a purist, but i think more people need to truly evaluate their needs before they start implementing.