Yep, this is exactly what I do. I got a smallish chest freezer for use as a lager chamber. Then I realized that I could fit a few 2.5 gallon kegs in it. I was starting to get fed up with bottling at the time, so I decided to go for it. It's a pain in the butt that my kegerator is out of commission while I have beers in active fermentation, but I use that time to drink down my stockpile of commercial brews.
My kegging rig is as simple as it gets. I have a 5-gallon CO2 tank and a couple of picnic taps. I don't have any kind of manifold to run multiple kegs off the CO2. I simply move the CO2 line to whatever keg I'm dispensing off of. I can't force-carbonate multiple brews at once, but otherwise I get by alright.
My next upgrade is a real-deal commercial kegerator. I'm getting sick of having to run down to my basement every time I want to pour a beer. But until that happens, this is a good entry into a kegging setup. I have no plans to add any collar or faucets to my freezer. Whenever I get a kegerator it will revert back to being a full-time fermentation chamber.