I have two 29" frames for Project 29er, a new 18" Kona single-speed steel frame an a used 18" aluminum Diamondback multi-speed frame. Both should be excellent frames. I'll be using either a 5hp GP460 engine or a 2.8hp Tanaka 47R engine. I've heard that 29" frames do well with bad roads and potholes. It's exactly what I need, since these bikes will be commuters in 25mph-35mph speed limit zones.