That's it-you guys have me jealous!
I am starting to look for an FZR400 frame now. If it's that easy to get an SRAD rear end on, then I can do a hollow rear axle no problem, and can tow my trailer with it.
A YZF motor in there, 90-100 hp, 15-50 gearing oughtta make it get up and go. And I have an USD front end that was taken off of a YZF600 superbike, so it might bolt right up to an FZR frame...and it's got a Marchesini Magnesium wheel on it to boot!

350 lbs would be lot of fun.