The mother of all wheelie bars.

[suicideneil]

I was planning to use a couple of skateboard wheels, but then I saw the prices of them. Then I thought about not using any wheels, but once I put that final little brace on, I realized a single roller blade wheel or similar (Rc plane wheel?) item would do the trick nicely.
I also used some 3.3spec turnbuckles- means I have spares which can be put to proper use if needed. The length is just about perfect for me too- going by my make-shift 1st version, the front wheels lift about 3-4 inches off the ground, but no further, which makes life much easier, less time turning the thing over back onto its wheels and such.