Thanks for your post.
Here is a direct link to an article I just recently wrote on what I recently accomplished.
Basically I took a Jornada 728, ran PocketDOS, which had first used FreeDOS, then I used the 486 BOCHS add on to emulate a 486. From this point I used PC99 a TI-99/4a emulator written in DOS to work on a 486.
The results were that it worked 100 percent as far as working, screen colors, text colors, etc. The bad news is that it was slow, but still playable.
I wanted to run the Scott Adams Adventure Module games on this unit, which I am doing, but wish the speed was a bit faster.
Anyway, someone suggeted that I look into MESS.
I sure like being able to have a TI-99/4A in my pocket now, and there were lots of great programs written for this machine back then.
Maybe you'd consider taking a second look at your coding to see what you can do. If so, let me know as I would be happy to beta-test for you.