When it comes to squirrel taxidermy, you can't beat Rick's Custom Squirrels.
From the site:
I have been mounting custom squirrels for over 20 years and believe you will be impressed with my work. I have had over 600 customers over the years, with very positive results. I use both Gray squirrels and Fox squirrels, whatever you may want. I use alot of vintage GI JOE accessories which look great on the mounts.