A bit late to reply, but in the hopes that someone else stumbles across this thread someday, I'll just say that I got the Kenmore 461.98475 on CL today for $50, with the blind hope that it'd work.
I'd checked a few other projects that made due with a 4.4 (or less!) cu. ft. mini fridge (the 98475 is actually 4.4cf, not 4.6, so I dunno if the CL ad you saw was misleading or what, but everything I've seen says 4.4), so I went for it.
In any case, it worked beautifully. I've only the 1 corny keg for now (clearance needed about 26" x 8.5" or so). But it sounds like others were successful with two plus the CO2.
The trickiest part was bending the freezer cooling shelf without kinking the line (that's the only cooling element in it, so it's important not to break it). Removing the door shelves was just a matter of a few dozen screws.
Didn't even need to cut into the plastic for this one.
So, to answer your question (though I doubt it still matters), yes, for me, the Kenmore 461.98475 was a viable option for a mini fridge kegerator.