I have persuaded the vendor of the following GPS-RTK units to work with me and the open source community to develop gpsd support for:
http://navspark.mybigcommerce.com/ns-hp-rtk-capable-gps-receiver/
These are low priced and hopefully good enough receivers that I'm planning to integrate into a design for precision agriculture robotics.
Please let me know what documentation other than in the links above you would need and WHERE to send their EVALUATION UNITS.
I will be the technical liaison for this effort since I'd like to have a solid gpsd client with regression suite as part of my application.
FYI: The device below "just worked" with GPS-XGPS on an Ubuntu laptop but the goal is to obtain RTK working on a Beagle bone.
Cheers,
Sriram
PS: gpsd appears to be an outstanding piece of open source code and architecture :)!