sdlsaginaw,
Actually, the anodizing shops love those little jobs like sets of grips. They need to put small parts in the corners of the anodizing tank to evenly distribute the electrical charge.
My brother used to run a big anodizing operation. He always chuckled about charging marine hardware manufacturers big bucks to anodize cleats and other small parts. He would have had to put scrap aluminum in the corners anyway!
Even if you find a shop willing to anodize your grips, you probably will be unhappy with the color. The shop is going to optimize his tank chemistry, current density and time for his primary workpieces.
I recall back in 2005 Rohrbaugh had problems with anodized color of the early frames - to the point where they couldn't ship finished guns.
Steve