I maybe wrong, but I don't believe XPort had a hand in porting all those emulators to the Xbox and calling the project Surreal 64.
The emulators two emulators used in Surreal 64, them being 1964 and UltraHLE, have not been updated at all since the last Surreal release. The only emulator that has been updated greatly is Project 64. The author of that emulator has stated though, that his previous source releases haven't helped him out alot, and the Xbox port was just a mere port and didn't help the project along at all.
So I'm not seeing an update to Surreal 64 anytime soon, unless the other emulators are updated and their sources still available.