Quique makes a 73" Yak that they claim weighs 11-12.5lbs. He has a video of it flying with a 26cc gasser, and while he's not thrilled with the vertical performance, it's enough to fly 3D and pull out of a hover.

Here's a link to the video: [link=http://www.qqaircraft.com/default.asp?s_nav=1&s_page=evo73_hi]click me, click me![/link]