Indeed it would not work immediately with the existing reprap code. Though I wouldn't say it needs a whole new code base, the changes should be relatively straight-forward, as long as the code base is properly abstracted between the various software layers. So yes I will admit there is an extra hurdle here.
Since I opened my big mouth, and probably inserted my big foot into it. I will take it upon myself to make the appropriate changes to the code, and build a prototype unit. It'll be a good first project for me to get into using makerslide
(I've been wanting to do an H-Bot design for a while now too)
I'll CAD my thoughts up over the next few days and hopefully be able to get in on the next order for parts.