SS, your elegantly demonstrated point is well taken re:space.
However - I can see a nice gap right in the middle of your panel just asking for a nice bit of hi-tech electronics.
Also I think you would have enough depth (25cm or so - I may be wrong).
The aerial is about 3 in and was mounted underneath. Your balls would be safe(ish).
I am sure Terra (Trimble) have a website - it really was a nice piece of minaturisation.
I had a europa monowheel - (much more space for kit like this I know) and put 500+hrs on it (in UK, Europe, USA and Canada) great little plane.
I'll be over with my saw and some wire drecly,
SB