Yes! It's not the easiest way, that's for sure, but it is possible. That's how I do it.
First, I use my Yooper Lagerator. It's an Igloo Ice Cube cooler. I removed the hollow plastic lid, and made a new lid out of three layers of styrofoam insulation. There's a hole for the airlock to poke through. Secondly, it's nice to have a basement or somewhere that is already pretty cold. My basement is right around 49 degrees, so I do the primary fermentation there. If I need a diacetyl rest (and I usually don't, since I pitch a huge starter cold) then I bring the fermenter to the upstairs where it's around 62. After the d-rest, I rack to secondary and put it back in the basement in the swamp cooler. I add the water, and cover it up. After a day or two, I add one frozen water bottle. The next day, I add another, etc. until I've gone down about 5 degrees per day until I'm at 34 degrees. I then change out the water bottles every couple of days, and keep it at 34 degrees for 8-12 weeks.
There are pictures of this set up in my gallery. I'll look for them and post them.