I just got back from a couple of weeks in Italy. I brought my Nikon D200 and a Casio EXZ-850. I shot a lot more with the Casio than the Nikon and I can tell you that my shoulder was thankful when i chose to go light. The Casio fits in the pocket or, in my case, I have a leather case that fits to my belt that I got on Ebay. I can tell you that the Casio shots were every bit as good as the Nikon's. The DSLR is useful WHEN you need the added features that go along with it. Unless you do, you are only spending money needlessly. BTW, the Canon elph also is a great little camera as are the Canon "A" models.
I recommend the suggestion of having your wife handle the merchandise. But when she is doing it, have her think about two things. Does she want to lug it around on vacation when the temp gets to 90+ and the humidity equals it? Will she regret not having the pocket camera available AT ALL TIMES to take the photo that she would not be able to take if she were toi go with the DSLR?