I removed all of the shelves from the fridge - both from the main compartment and from the door.  I fabricated two pieces for the fridge - a platform for the kegs to sit on, and a shelf for the CO2 tank in the back.

The kegs needed the platform because the bottom of the fridge is uneven - there are ridges, partly for the drawer that originally went there.

The co2 shelf is necessary in order to fit both kegs in the fridge without removing the inside molded panel from the door.  It rests in the rails on the side walls for support, is narrow enough behind the kegs for them to fit, and protrudes as much in the middle as possible to hold the CO2 tank.  A vertical piece of plywood lends support to the center, as the whole shelf would twist under the weight otherwise.  It is more than stable enough to hold the tank when at least the left keg is in place, but I don't trust it otherwise.  Someday I might put an eye hook in the back or top of the fridge so I can use a short chain or rope to prevent the co2 tank from falling off the shelf, just in case.

I recently finished plumbing up the second keg, though the pictures don't reflect that yet.  A brass Y-splitter and a second shutoff valve gave me the second CO2 line, and another 6-7 feet of beverage tubing hooked up the second faucet.  One thing to watch out for is that the hose barbs on the cornelius disconnects are usually 1/4", but the barb on the shutoff valve I got was larger, maybe 5/16" or so - I bought tubing to fit the larger barb, and had to scrap it and use some 1/4" vinyl tubing I had lying around instead.  The 1/4" ID tubing was not too hard to slip onto the larger fitting, after running it under hot water as always. 

And yeah, I still need to clean off the sharpie marks from where I marked out the drill holes for the shanks in the door.   

Platform and shelf in place

CO2 tank and one keg in place

Both kegs in place

Shank mounting details

The money shot