Originally Posted by
az2008
I seriously doubt those are proprietary. I bet you could swap either the derailer or shifter with Shimano and it would work.
+1. On the derailer tip you could even take it farther - Almost any non-RapidRise long cage derailer made since 1990 (EXCEPT Sram with numbers in the model name) plus a claw adapter would likely work. That's probably about 95% of the long-cage rear derailers sold.
If I were replacing it I'd probably just get a lowend Shimano with the claw already on there.