A group of people at  have for some time now been analyzing ADS-B specs, and the construction of commercial ADS-B units (AirNav & Kinetics). Under coordination of "Vinculum" they are now trying to make their own version. From the information released on the website there is a working prototype at this moment giving very good results. If and when this project comes to an end, the fruit of this effort will be sold as "kits" with PCB, filters etc for a two digit figure (euro)!

1090 Mhz ADS-B Receiver project info page. Unfortunately the whole discussion and website is in German. The developer needs to know how many people would be interested to buy such a unit, to place the proper orders for the components etc, and also help to keep the per-unit-price down. If you feel you want to experiment with ADS-B send him an email: webmaster_removethis_@jetvision.de telling him you would be willing to purchase one (or more). There are already twenty people on the list.

/geraki