Not sure if you experimented with FamiTracker or not, but I think some SEGA tunes would sound good on that application...would you happen to have any knowledge of it to knock up some NiGHTS or Panzer Dragoon on it?
GarageBand on the Mac works in a somewhat similar fashion but with real instrument samples and if you know how to read and write music, it can be applied that way along with sample loops and the ability to add your own audio track via MIDI or line in on the Mac.
It's essentially a poor mans logic pro/studio.
How far you can push it depends on how much power your CPU can muster and a huge amount of RAM. Tried uploading my track onto YouTube earlier but the servers are swamped! I have a 30Mb internet connection and I can't even get video's to stream tonight. Much of the work I did in the past was with a PC, and Cakewalk Pro. Using what was formerly a beast of a computer, my phone now outpaces.
Something sparked a fire in the tower and my data was roasted save for important projects that I backed up to CD-R along with custom soundfonts with the original Sound Blaster Live! audio board.
So without my old rig, I bought my Mac and never looked back.
I will have that track uploaded hopefully tomorrow.