JL, to get the best squirrel rifle, I wouldn't advise buying another gun at all.
(Oh, my God, did he really say Don't buy a gun?
)
Take the money you would spend on a new rifle and invest in a first rate trigger for your 10/22-either install the parts, have it done, or get a whole new trigger group.
Then, once you have a good trigger pull on the rifle, get a first rate scope. By first rate, I mean a 1" tube scope with the parallax set for .22 distances, or an adjustable objective. Expect this scope to cost as much as a good scope for your big game rifle.
Leupold makes a 4X and a 2-7X designed for 22's, and the Burris R/A series (rimfire/airgun) would be 2 examples of the type of scope I'm recommending.
With a good trigger pull and first rate optics, I think you'll find you already own a great squirrel rifle.