I've been doing up a page that's somewhat of a blueprint for what I have in mind.
This is what I've got thus far.
CarCycle Design
I will fully admit it's not the most well-designed, or lightest frame, but I don't have access to plastic moulding or a wind tunnel, and like I've said before, I'm definately on the hefty side, so I need something sturdy and stable
UPDATE: Or is my issue here simply underestimating how strong steel is?