Any recommendations on a great ultrabook or thin-enough laptop with great battery life for running Ubuntu?
Dell has XPS 13 super expensive ultrabook preloaded with Ubuntu. But technically you can buy any ultrabook or zenbook, and blow windows away and install Ubuntu in it. Few models I would suggest to look at are, Samsung Series 9, Zenbook, Vizio ultrabook, hp envy spectre. I think in the end it really depends on your budget.
I personally would buy an ultrabook which has Windows 7 with it (not Windows 8) and dual boot it with Ubuntu.