Is there a place I can get some polished stag for some CW material?

I could be wrong (have been a lot in the past) but I always assumed the shop did the polishing when the knife was in build.

You might be right, and this might be an impossible find.

The shop only supplies polished stag for the centers on model 25-style handles. I was hoping to get a piece for a full handle. But it is looking like finding a piece with the exact right dimensions may be impossible.

Neale is correct. I'm sure the shop starts out with smoother pieces, Keith. Try and find examples that are not "gnarly" and slightly larger than what your requirements call for. You can then put in the "elbow grease" factor yourself.
I am not in the habit of selling my handle material. It is purchased with the idea of making certain knives or custom "ordering" certain knives for folks. Out of over 100 pieces of crown stag, I have found 2 in my searching that are, not only huge, but polished. Good luck on your search. (But start out looking for crown: The stag is larger at the base)
Best, Capt. Chris
PS: Here's a couple of pics of "one" of the pieces I have in stock. It is shown with a couple of nice "bark crown" examples as well...CCS

Cap,
That's a beauty! Did you buy it polished or did you have it done for you?
Tony

I bought a matched pair...already polished. They do not appear to be off of the same critter...I'll post photos when I get a chance.
Best, Capt. Chris