Depends on a few things. How are the cooling lines oriented? I've modified 2 mini-fridges. They were both Sanyos with the U shaped freezer compartment near the ceiling of the inside. You simply remove the clips on top and slowly/carefully bend it back so it now sits vertical against the back wall. Not ideal since it's still there, BUT that IS the cooling element. No worries about drilling through the cooling lines when poking the holes for lines. If when drilling you hear a...ssss...you might as well get a new fridge.
That shelf at the back is the compressor hump. It does interfere with getting a corny keg in there sometimes. You can usually perch a 5 lb CO2 tank back there, but that often gets tight as well.
If you use a dedicated freezer, you would need a temperature controller which can add $50-80.
Primary #1: Umlaut my Kölsch VI #2: Sunrise Wit
Secondary #1: Empty #2: Black Currant Wine #3: Empty
Bottles: Spruced Winter Warmer, Big 50 Barleywine, Framboise Lambic, Russian Imperial Stout, Barolo Wine, Berry Rhubarb Wine
On Deck: Dusseldorf Alt III, BGSA