How hard is it to do this? What does one need to know to carry out such a project?

I ask because I'd like it to cut down on the weight of my rig.....my amp weighs about 50 pounds and it's kind of a pain. How much weight would making it a head cut out?Those of you who want to make fun of me, go ahead as long as you have some insight on the topic.

Stage Rig

Fender Strat
Epi Les Paul
Taylor 110
Boss TU-2
Omega Amps Hot Rod Deluxe (Dumble mod)
Clean/Drive/More Drive footswitch
Mid boost/Preamp boost footswitch

Its probably possible, just remove the electronic from the enclosure, then make an enclosure for an head and put it in it. If have no experience in woodworking, just find a local worker, I think it would work you an external speaker out on the HRD, maybe I'm wrong though.
you can remove the electronic components and build an enclosure out of plywood, and fill the gap on your cabinet with plywood. Wire the speakers to a 1/4" jack and wire an output as well. Record the ohmage of your cabinet as you'll need to know for future reference on other cabinets.