I’ve got a second refrigerator in the garage that could hold, it seems to me, a keg, the CO2 cylinder, and the hardware, all within the fridge itself without drilling through the doors or walls. I could then try out having a kegerator with existing equipment and not wind up “breaking the other refrigerator”, in wife’s words. Couldn’t the tap be mounted on a piece of wood or something and just sit on a shelf inside? I don’t mind the thought of opening the fridge every time – I’m already doing that anyway, right?
I’ve seen it done with soda kegs, without even mounting the tap; it was just on a length of tube. You open the door, pull the nozzle out, dispense, and put it away. No biggie.
As long as the keg, tubing, taps and CO2 tank can fit inside, then yes it’ll work. When I built my first kegerator the only hole I drilled was in the refrigerator door for the tap. You’ll probably want a picnic tap, they’re the small black plastic ones.
I have at least three friends who keep kegs, gas, and tap inside a fridge. One of them doesn’t even have an extra fridge for it - he removed all the shelves but one. He doesn’t keep much food there, but he always has a few kegs of home brew.
-D/a
Try to convince your wife otherwise. You’d not be “breaking” anything. If the kegerator didn’t work out, you could fill the holes with J.B Weld. Actually, you could do a proper patching job.
Use logic with her. Holes don’t “break” anything.
Background: the fridge that come with my house has four holes in it. Two taps, and two CO2 lines. I keep the CO2 outside, since a 20 pound tank won’t fit inside. I have two separate CO2 feeds (one would probably work) in case I want to add a separate regulator, 'cos I have a 1/2 or 1/4 barrel of commercial stuff inside, and also my Cornelius keg with my home brew. They both fit. In fact, the holes are the least damage I could have done. Taking out and throwing away the shelves and crisper and building the wooden shelf were far more destructive towards the future possibilities of return the fridge to its original use.
Most of the people I know with upright kegers/refrigerators just take out the shelving and stick the entire apparatus inside, hoses, CO2 units and all and just open the door when they want beer.
I have a converted chest freezer that holds 4 kegs and four taps - no drilling involved. Basically, you pop off the back hinges, and remove the top. Build a new frame around the outside edge of the freezer and drill your tap holes into this. Attach the freezer top to the new frame, add some sealant, slap on a temperature regulator and now you have kegerator and something that doubles as a bar as well.
Enjoy your beer. 
As suggested above, get a kegging setup with a ~5lb CO2 tank that will fit in the fridge. Use a picnic faucet instead of a traditional tap while you evaluate, then add a tap later if you like it.