[Tyhm]

Last I heard (years and years ago), the theory went that if Graal is built as Kernel and Emulator, then Stefan has but to make a single stable Emulator on any platform he likes (including key-mapping, etc) then update the Kernel seperately and Voila, it'll be an update for all platforms at once.
Graal on the PC!
Graal on the Mac!
Graal on the TV!
Graal on the cellphone!
Graal on the microwave!
Graal on the toaster!

Trouble of course was that the Simple Emulator had to handle little things like How The Various Platforms Handle Image Processing, etc...which led to the long string of "This weird error only happens on Macs", which led to a lot of Case Selection on the Mac client, which may have scrapped the Multiplatform Graal Effort. Who knows? (Well, Stefan probably does, but he's so busy with G3D under the theory that All Graal Needs Is Another Good Project, not tools for players to build their own content and market their own servers and bring in their own playerbase, perish the thought...)

Awe man, what're the odds Stefan'd post a more definitive answer in the 7 minutes it took to type this? Ripoff...;-)