The UK ATC authority, NATS, has implemented a trial with AOPA UK to test a low cost ADS-B out capability. Basically, they are allowing non-certified GPS to interface with the Mode S 1090ES which gives ADS-B out.

Some people have (illegally) tested this with their Trig and other transponders in the U.S and other places:

This is as much as I know...

http://www.nats.aero/news/nats-enabl...-ga-community/

Hope this pans out... and FAA is listening.

Walt Rogers WX