Yes you can, actually. Anything Ubuntu can run on now will support Ubuntu TV. In other words, 99 percent of PCs and all the Ubuntu capable Android devices out there, and if OpeniBoot ever stops sucking ass then iOS devices would get it too. Basically anything capable of handling Ubuntu. This will be interesting to see as it's open source, and devs seem to love getting Ubuntu on Android devices.. Could we see a Logitech Revue running UTV? Who knows.
Although it does require 1GB of RAM no iOS device to-date can handle it. I'd love to see it running on a Apple TV. http://www.youtube.com/watch?v=Sacw02rCicg You can install it here. Provided that you are running Ubuntu 11.XX.
Depends on the TV. Even the ones that do have RAM probably would only have less than 1GB. your would be better off getting an HDMI dongle with an ARM processor, or even the one mentioned in a link right in this thread.
I've been thinking about getting a dongle for my computer anyway. I bet it would look great on my HD monitors! Thanks.