A "keezer" is based on a chest freezer.
A "kegerator" is based on a fridge.
I don't think anyone actually retails keezers, your best bet is to buy the size chest freezer you need and build it yourself.
There are plenty of companies that sell kegerators. Don't know whether you can buy one stripped down to just the fridge unit, but frankly you'd do better to just buy the right size fridge and build a kegerator yourself at that point, as there's no real added value in a stripped down kegerator, yet you'll likely still pay way more than what a fridge of the same size would cost.
All three of my beer chillers (two fridge/freezers and a keezer) were bought from Craig's List for stupid cheap money. I highly recommend going that route...