Call me crazy...but this does not sound like a very good idea, AT ALL! Interesting idea, but not a good one. Especially not from a married stand point. Please don't take offense to this, but it sounds more like a last minute ditch effort to save some cash on your wedding. It's not bad to try to save some green on your wedding, but maybe in other ways.
Believe me, you'll be too busy to take photos. We just did my daughter's quinceanera this past Saturday and my wife insisted that I take photos. I fought, and fought, and told her that I know I wouldn't have time...and alas I was right. I was able to take about 20 photos the entire night. I was just too busy with the party.
DJ: "It's time to cut the cake...."
Wife: "Let's go cut some cake and let's cherish these memories forever!"
You: "Wait! I need to get my camera and take photos of the cake cutting so we can have these photos in our album."
Wife: death stare.
I hope you can see where I'm going with that little monolouge. Is your wife going to be the only one in the photos? What about photos of your first kiss? First dance? Garter & bouquet? Formal portraits? Are you going to be standing at the alter with your DSLR and your face buried behind the viewfinder?
It's a novel idea, but I don't think it's in your best interests to be your own wedding photographer.