Try Satel’s Satelline-4Pro. Satel manufactures the internal UHF radios in the GS14, GS15, GS16 & GS18. It will broadcast one of several different modulation types including GMSK which is utilized by the older Trimble systems. As for power consumption, at 25w I have been getting two 10+ hour days out of a single charge on a RV battery.
This summer I have been running a base/rover system that has included GX1230s, GS14s, GS16s and R10s without any problems. As for compatibility, Smartworks has a pre-defined device type for the older version of the radio which works fine if you change the baud rate. That is not a problem though, since all the base receiver needs worry about in the was of configuration is the serial communication parameters. Everything on the broadcast side is controlled by the radio.
Look at spending around $3k for a system.