We could call it "Android"
The only problem here is you're looking at writing everything, or porting from other OSes. At that point, you might as well just port the whole thing and get rid of WinMo core too. If I were going to work for free (and I'm not

) I think getting involved in an android port would be time better spent then trying to come up with yet another layer over WindowsCE Core.
To see why you have to write everything over, just take a look at TF3d - really nice experience, weird behavior with WinMo notification interactions, and "oops I fell off the edge of the world" experience as soon as you drill down to the kicking-it-old-school window mobile apps.