In my opinion the problem of other OSes always comes down to availability of the sources or the ability to compile a new driver.
Unfortunately just the same CPU in a Winmo or IOS phone does not mean all other components of the system are the same. There could be a whole lot of other differences like other sound chips, different charger ICs, different power management IC that require changed drivers. Thus a 1 to 1 port might be possible in some rare cases ( e.g. for some HTC phones ) but for the jet I don't really see this.
However, the same CPU helps on parts beyond the kernel and drivers. If there is an Android phone with the same CPU as the jet we can surely benefit from this phones system binaries. The same thing should work for other OSes, too.
So, back to the original question. Possible other OS options should be symbian (sources should be available), Meego (also open source) and maybe even Bada (not open source but i recently learned that it is also based on a linux kernel). That's what I currently see, there will surely be more ...
I hope this helps.
Cheers,
Dopi