It looks like Moorechip has made an official grip for the RP3/RP3+ which will definitely be useful for FPS games which are uncomfortable to attempt to play without a grip, and it will be available after the holiday ends (sometime in February) at GoRetroid.com.
Photos via: https://www.facebook.com/groups/3142736962715416/permalink/3454545248201251/?mibextid=Nif5oz
