Hello, I just wanted to take a chance to plug MESS: http://www.mess.org/ It is an open-source, multi-system emulator for old computers and game consoles, based on the MAME codebase. If someone is interested in writing an emulator of an old system, this is one way to go. There is definitely a learning curve, but there are preexisting modules for many microprocessors. If anyone is interested in exploring this, feel free to contact me directly. Thanks, -Frank