This is a cabinet I had a friend build for me about 15 years ago. At the time the only rig I had was my dual Bassman/4x12 setup. It was a great rig but a bitch to lug around. I wanted something I could take to jams that was a little more portable. I decided to build my own and save some money.
I basically decided on the width and depth by measuring one of my Bassmans, then adding a couple of inches all around, then making the height big enough to hold the speakers.
I did the basic measurements, bought the wood, and took it to my woodworking friend. We put it together in a couple of hours. I had the handle from another amp I parted out, and cut a piece of tin for the jackplate. It's wired in hard stereo, that is, two jacks, one to a speaker. I had some insulation laying around and put it inside the cab. A couple of coats of paint, and there you are. No grillcloth, I'm surprised I haven't poked a hole in one of the speakers after all these years.
There was no internet, no Ted Weber in those days, all I had was Parts Express. The speakers are 100 watt Pioneers, believe it or not. They don't make this model anymore, umfortunately. They sound pretty good, and the 100 watt power rating is helpful when I run a flat out 50 watt Bassman into each speaker. The cab doesn't have a lot of low end umph, but other than that it sounds very good. I recorded the first Reign CD mostly with this cab.