I have seen two on Evike and various other sites that are made to attach to a m4/m16, and are made to house a motor. The M14 motor is housed in an awkward position ahead of the collapsible stock, therefore I do not need a motor in the grip.
=)Oups... Didn't know that!!
I've only seen the WE M14 and forgot it uses V7 GB!!
I am going to have to look around at the RS versions and see if anything comes relatively close. It would be a real debbie downer if I can not find a replacement... But then again, maybe I will just modify the stock grip. Shave it down and give it a leather job or something.