"...Used transponders that would work are always for sale .."
Thanks for that reminder Mike. I didn't know the used prices got down that low. I'd probably have to add about $200 to that to have the avionic guy install and certify it So,. Might do it at some point. Issue remains though of not a square inch left in our basic LSA's panel.... bit of a puzzle where to put one, unless we paid a big prenium for one of the tiny ones.
Thing is, I never fly in airspace above class-D, so not required to have a transponder or ads-B ... Just wanted to be more visible and had hoped that even without a transponder ads-B out would do that and even let me use flight following. I think point of my post in part was, incase someone else had that hope (ads-B out useful without a transponder) not to hold their breath waiting for that.