Re: Good double action pistol
You might also consider the Sig Pro SP2022. Polymer frame, Stainless slide. DA/SA & 15 rounds of 9mm or 12 of .40 or .357 sig. They're getting pretty good reviews from the Sig regulars.
Re: grips for sig 220?
The Hogue flat panel grips are an inexpensive alternative to the finger grooves for smaller hands but as somebody else mentioned G-10's are the ticket. Nills are gorgeous but for a carry gun, I'd be afraid of damaging them.