I think Thomas B. has some info on them. I talked to him a bit about where to obtain one over a year ago. He seemed a bit hesitant to recommend one (yes the rocket powered one) for R/C. It has been done and I seem to recall it being a pretty simple setup.
From the reports I recall (years ago) the fuselage shell is quite fragile, especially loaded with lots of weight? Perhaps the B20S direct on some really tiny nicads would be your best bet. Keep it light perhaps.
Should be a simple matter to make an adapter to press fit the B20 into the 'tailpipe' so-to-speak.
I wish I could get my hands on a few of the kits. Would certainly bea fun project.
Anyone have one sitting around?
Have fun with it and keep us informed on the progress!
PS - gosh I just read my post and I didn't give a whole lot of infor there did I?