Structural Framing is a great way to build your robot, as it is extremely flexible in the way it is placed and assembled. There are no other methods that I know of that give you that level of adaptability. If you know exactly what you are going to want to build, there are better options out there, but if you want to be able to "move things around on the fly" Structural Framing is awesome.
That being said I would highly recommend using the Kit of parts drive train, and adding framing on top for your mechanisms.
My company REV robotics, just announced our structural framing system which will be sold through AndyMark, and available in the next week or so. We designed it specifically with FIRST robot applications in mind and did everything we could to make it an affordable complete solution for teams. You can check it out here,
http://www.chiefdelphi.com/forums/sh...hreadid=131136