With regard to buggy, did you try True Basic under WinUAE ? I ran it under Workbench 1.2, should suffice if it was available at the time. Tried different memory configurations but no luck, just comes up with a software failure. AmigaBASIC on the other hand runs on my 1200 and WinUAE as well as any other system I tried it on. So I would be careful to say it is buggy. I still would like to try it, maybe you can test it and upload a working version ?!
The only commercial game I know that was written in AmigaBASIC was Arazok's Tomb (could be wrong). Was a decent adventure game I think and not PD quality. I have seen commercial games that are worse than PD games though not written in BASIC.