I don't think it is. I'd like to examine it as well. The preemptive multi-tasking scheduler can be very useful for games, and it may be possible to port it to other 8-bit computers.

And, if software could be made portable, it'd be interesting to have GUI software that's cross-platform between Ataris, Apple //s and ///s, and the Commodore and BBC families (a VIC-20 would need a lot of expansion). Sadly, most of the others run their 6502's at half the speed of the Ataris.