A buddy of mine on here, GRegister has said that there is a way to turn your Rushmore radio into Sena 20 compatible blue tooth.
This is the text he sent me: I'm now convince Harley will never offer a Bluetooth setup better than the one from Sierra Electronics. Their harness is only $160, but you'll need a Sena SMH10 module also installed for $112. So for $270 the bike will be compatible with all Sena Bluetooth headsets, including the Sena 20s. Checkout the 20s.
For those wanting a fully bluetooth Rushmore radio, this sounds like the ticket.