The "problem" with the little mini-fridges is space. Just about every one of them comes with that stupid freezer unit, which takes up valuable space.

If you end up getting a mini-fridge, you will probably end up having to seriously gut it out - as in busting out some of the plastic and insulation in the fridge. it won't look pretty, but it will work.

I did that back in the early post-college days. Had to bore lines for the C02, as it wouldn't fit in the fridge with a 1/4 barrel. Front tap just barely fit with all the hoses, etc.

The taller/skinnier 1/4 barrels were much easier to fit then what I have pictured above - which is pretty standard these days.

Tougher to do - and you definitely will want to measure out a quarter barrel keg and the inside dimensions of the fridge before getting one. Don't forget that the top of the tap and line will take up more head-room space in that fridge than you'd think. See that nice relaxed bend in the black beer line extending up and over from the tap? If you squeeze that line too much, that will kill your flow of beer - and that's bad.

PM me if you want the conservative measurements of what I would consider to be necessary for the insides of a beer fridge. I can always go measure the keg I have now for you.