I just got my On Course Navigator 8 card today and I works great! I had a bluetooth GPS (thanks Verizon for locking the internal down!) and had my xv6900 connected with bluetooth and it was full screen and wonderful!
BuyGPSnow has it on a 2GB card for only $49.99. It says it is for 5 days only and I ordered mine on the 8th so I'm not sure if it will expire or if it is a marketing ploy....