I had never heard of that device, I had to look it up. (http://en.wikipedia.org/wiki/O2_Joggler for anyone else that is curious).
As for your question, it does depend on what your looks requirements are. I'd consider using thin plastic to build the frame, solvent welding it together than painting it with Plasti-dip.
I've read that bondo can carck over time, as it expands/contracts at a different rate than the plastic, so don't just gob that on or it may not last.