22/45 Grip Frame Choices
I called this project a 22/45 because that is the style grip frame I am planning on making for the parts kits, but you actually have lots of options, you could use a grip frame from a MK 1, 2 or 3. The MK 3 is better, it has a thumb mag release.
The aftermarket Volquartsen grip frames also work well, (expensive) two styles pictured below, the first is the 1911 style that will be the style in the parts kits:
Below is the MK style grip frame that will also work for the receiver.
Below is an unfinished model of the frame I plan to produce for the kits. It is modeled after the Volquartsen but I changed the trigger guard a bit: