Sources for DIY avionics???

[First post after lurking for quite some time...8-)...]

MANY years ago I built up quite a few kits that I got from RST (thanks to
Jim Weir!) and really enjoyed it while learning alot. But that was more than
20 years ago. In looking around lately I can find very little that would be
suitable for DIY. As a product designer for the last 25 years I realize
that much of the technology has moved beyond the capabilities of the average
DIY type (surface mount, custom ASICs, etc.) - BUT - is there anything out
there?

I would like to build a number of things (e.g. remotely controlled VHF
receivers, ADS-B, etc.) but it looks like I'll have to go it alone and
design them from scratch. I'd be interested in hearing from any of you about
things you've seen out there as well as any potential interest in getting
involved in DIY avionics.

Sure, most of the off-the-shelf stuff is cheap and available, but if any of
the new NASA/FAA initiatives really come to pass (AGATE, SATS,etc.) there
could be a real need for modular, inexpensive widgets and functional blocks
that could be integrated easily into a custom "system".

Any pointers/comments most welcome!

Regards,

Bill-the-lurker