>Between Android, iOs, the remnants of blackberry and the Microsoft offering there will not be a whole lot of room for a new entrant that is not compatible with any of the above
It seems exceedingly likely that if more than a few dozen people use this, someone (if not Canonical itself) will produce an Android compatibility layer.
What I wish Canonical would do is to do it right. The naive implementation is to take the existing Android source and hack it into Ubuntu like WINE, which is almost certainly a lot easier when the source is already available. What Canonical ought to do is superset Android natively: Make all of the APIs available the same as they are on Android, so that you can take the source to an Android app and just run it on Ubuntu, but you can also start from there and make relatively few changes in order to comply with any differences in Ubuntu's usability standards and have your existing Android app running properly and natively on Ubuntu in very short order.
That would give Ubuntu all of the Android apps right away, and then give Android developers an easy way to fix any compatibility-related issues with running those apps on Ubuntu without making significant changes to their existing code.
Meanwhile now you have Android running next to POSIX and developers have the temptation to use all the traditional gnu stuff plus whatever Ubuntu adds to make it appropriate to the form factor, which has the developers pushing Google to put that stuff in Android.
There is a foreseeable future in which Android and Ubuntu end up as different distributions of the same basic OS the same as RedHat and Ubuntu today.