At the pixhawk site: http://pixhawk.ethz.ch/wiki/electronics/communication  there is a note on RF modules from Lairdtech, (LT2510), which is supposed to be pin-compatible with the xbees.

On Lairdtechs productinfo: http://lairdtech.thomasnet.com/viewitems/2-4-ghz-modules/lt2510-fle...  it is claimed they can be co-located with other systems, which makes me think of a possible co-location with a 2.4GHz receiver.

Anyone who have experience with these modules or who have oppinions if these modules might be an alternative to the xbees ?