Whitecap: The materials that I used are micarta and bocote wood. The bocote is similar to cocobolo, and I believe it comes from south america. The micarta is what they used to use for PC boards and other things before fiberglass g10. It's made from layers of either paper, linen cloth or canvas material bonded together with a phenolic resin.
I did a quick experiment with one of the scrap grips and made a mag release relief scallop. Looks a little funky with the deep checkering but it does make it a little easier to get to the button. I also have some other texture patterns drawn up in cad but I haven't machined them. I guess if there's enough demand I could experiment with different things.
Dave
Couple more pics:

Scallop experiment

Black linen micarta on the mill before checkering