Leady - many thanks for the detailed background to these issues.
What if we had low level Class E wherever radar coverage exists on the J Curve?
A few years ago I recall this came up during discussions @ RAPAC, and a bunch of sport aviation types including gliders, hang gliders, certain ultralights etc. had exemptions (CAO 95??) from the carriage of transponders in Class E, if they didn't have an engine capable of powering one, and that lack of visibility to ATC and transponder-equipped aircraft seemed to be an issue for low level Class E i.e. down to 700FT AGL.
Anyone know if these exemptions still exist? I assume they still do for gliders.