I have the G27 (.40 version of the G26), and I like it. The only issue that you might wish to be aware of is that even with the Pearce Grip extenders (and there is a +1 to take the .40's to a 10 rounder), there still feels like there is no support at the bottom of the hand (mostly in the palm area. This takes a while to get over, if you are used to the full or compact sized guns (vs. the subcompact that the 26 and 27 are).
See about taking her to the range, see if she can handle the .40 in the sub-compact, and encourage her in that direction if you are looking at the G26. The extra power with the same size is a plus that I have chosen personally to go after.
And oh yeah, congrats on a great wife (one who shoots). Many of the guys out here have women who don't understand this crazy stuff! [:)]