Yeah if you read thru that little pinned topic named "Request For New Projects" X-port actually explains exactly what is needed, and why, to port something over to the x-box.
I believe the saturn emu was mentioned in there as well. First post actually..
QUOTE
Cassini/Saturn - While technically the source is available for this Saturn emulator, it is primarily one (very) large assembly file which looks like it was created by simply running the GiriGiri EXE file through a disassembler. Porting x86 assembly to the XBox is not generally a problem, but in this case the code makes all sorts of calls to Windows GDI routines that are not implemented in the XBox SDK. This means that in order to port it, I'd have to implement those API calls myself or try to hand-edit the assembly file. Both of those tasks would be extremely tedious and therefore this project is not something that particularly interests me.