From what I heard, the 29" does have advantage of able to roll over "stuff" a lot better than 26". If I am buying a HT today, I would opt for a 29" and take advantage of that.
I currently own a 26" Giant Anthem from 2008 and plan on keeping it for a while longer. I am getting older and not plan on racing. 26" XC FS still serves me well.
I don't worry about the tire and rims support for 26" now cause there are still plenty of 26" out on the road.