Im going to advise against a 4x12 not only b/c of the size but also the 4x12 is actually the worse speaker design. The only reason it exsists is because in the 60's Jim Marshall made 100 watt amps but only had 25w speakers. The 4x12 design has a muddy bass and tends to beam treble so you get in your face peircing treble in front of the amp but theres a drastic drop off if you move to the side.

Someone on another forum was claiming that he got more bass from a ported 2x12 than a 4x12 with the same speakers. if one 2x12 isnt enough you could build two and you'd wind up with much better bass response since all 4 of the speakers will be "on the floor" the 2 top speakrs in a 4x12 design would be trying to push the bass through the air which does not travel far. Bass likes walls and floors to travel through thats why you never see subwoofers off the ground.