Wow that WinUAE Loader looks great. It seems it does similar to my GBLauncher.exe (i.e. run GB games via command line). I'm assuming it would only work on GB Amiga, and not other GB databases (such as GB64) but I may be wrong. I'll download it and have a play when I've got some time.
It would be nice if WinUAE Loader outputted gamebase gamelists in romlister (xml) format - then it could potentially be used in a variety of arcade cab frontends.