Richard D. emailed this from the s/v RED in Alaska:
I ran across an interesting OEM GPS Compass module that looks like it could bring down the cost of these devices if someone packages it. See:
http://www.hemispheregps.com/Products/PrecisionProductsGroup/PrecisionProducts/LV100OEMBoard/tabid/412/Default.aspx
http://www.hemispheregps.com/Products/PrecisionProductsGroup/PrecisionProducts/LV100OEMBoard/tabid/412/Default.aspx
The Hemisphere GPS compass is a serious piece of kit,
Very expensive so would imagine the OEM board (hemisphere gps without the cable and case) would still cost much more than say a Koden KGC-1 or Furuno SC-30. to buy before a case etc was built.
I'm pretty sure it's done.
http://www.comnavmarine.com/html/cmnv2340.htm
For those seeking a less expensive gps compass you might want to look at http://www.kagstrom.no who has a piece of GPS compass software that works from two independently mounted gps receivers. Someone could make some interesting products from that. Not a replacement for the commercial boxes but an interesting choice if one combines it with something like Maretron SSC for stable autopilot and radar directional headings.
I have the hemishere oem board, its a low cost solution and a good one.