Actually, what would be really cool is if the FAA did something smart
and mandated a FLARM-like transmitter in anything that flies. Maybe
adjust the power output to depend on aircraft speed. If we could
bypass the TSO/STC and other requirements and just let the thing go out
with the notion that it will mostly work, I'll bet the entry price
could be $100 or less for ultralights, and certainly less than $1000
for a top end model with color display.

Should eliminate the need fo Xponder in most sailplanes, and think of
the added safety at uncontrolled airports, where we tend to have too
many incidents in and near the pattern.

But of course, this is too simple and inexpensive a solution.

-Tom