I will be posting a how-to very soon on my site on what exactly I did but here is part of it.
Set your windows background to plain black. Make the taskbar so it auto-hides. Set the color scheme to high contrast Black. Then go in and customize it and make the title bars black too (instead of purple). Have your Mame front end launch at start up OR use Party On to launch at startup then launch your mame front end from there along with any other windows program. The few seconds that your windows desktop is shown for will look black, and won't appear "windowsy" at all. You can remove the desktop icons with tweak ui except for my computer. For My Computer go into paint and make a tiny pic solid black and then save it. Now set that as your my computer icon. Drag My Computer icon to the bottom until the text "my computer" is hidden below the screen. You won't be able to see. I just put mine in the lower left. There are also some programs that'll get rid of desktop icons altogether.
AD