Here is a feature request that I'd had in my head for quite some time now. I don't usually pass my crazy ideas on down through the devel pipe, but I feel this one is too good to pass up on.
Many of us still use desktop mode to get around issues with various window managers (compiz, metacity, etc). But running a game in desktop mode, you loose out on running full screen.
It would be slick if the Wine desktop could be switched into full screen on the fly with a hotkey (say Ctrl + Alt + Enter). So if you are running a 1280x800 Wine desktop on a 1680x1050 screen, and you hit the hotkey, the resolution would be switched to 1280x800 and the Wine desktop is your screen until you hit the hotkey to switch back, or you exit the program.
Sound fun?