Asus Padfone 2
I think with Asus and Canonical's relationship being pretty good, they did just release two new netbooks with ubuntu on it, that the Asus padfone 2 would be a perfect candidate for "Ubuntu for android".
My idea would be that when the phone is in the tablet it would still remain in android, but when you attach the tablet dock to the keyboard dock, it would then switch over to ubuntu. This seamless transition would make it more productive in the business world. And it is something I for one would definitely find useful as I am in the market for both a new laptop and a phone. I love Asus and think they put out quality products and that would be a product I would back.
On another note if the even used ubuntu for android in their tablet series i think it would make their products even more viable to the mass market. That way you have android on you tablet and when you dock it to the keyboard it switches over to ubuntu. Even this would be something i would consider buying.