XBLA would probably be possible, they have games that run using flash i believe
[quote:2fwezqe1]Published: January 3, 2006 7:56 AM PDT
By Marcus Lai
Hackers have cracked the Xbox 360 puzzle game Hexic HD in order to discover more about the inner workings of Microsoft's new console. Files from the puzzle game have been extracted, burned to disc, and booted from a standard Xbox 360 console. The game can also be run on PC.
Hexic HD, a puzzle game included on the Xbox 360 hard drive, is said by hackers to be a simple Flash application that is common code to basic computer software. The new discovery is a step toward running unauthorized software on the Xbox 360 console.
The previous Xbox console became a hackers playground for running unauthorized media files, including pirated video games. Microsoft has made an effort to curb piracy by including prevention schemes in the Xbox 360, however persistence among the hacking community has yet to see defeat.
In 2002, the software giant took legal action against online import store Lik-Sang for selling Xbox mod chips that enabled users to bypass security software and run pirated games.
so yah i dont think it would be impossible to make .exe's made for windows run on a console that runs on windows, and uses direct x9. im sure someone with a modded console has tried this somehow. i know you can run NEScafe through media center