YES,
I bought one years ago, modified it and moved to BC from Ontario with my Ex, 2 dogs, 1 cat and 250+ birds! yup you read that one right!!!

The benches I used a torch to cut out, next time I would use a grinder or a high speed air grinder/cutter as it would not do as much damage to the metal as the torch did. On my blog and on there I wrote a review on it. There are too many windows, so after a while, I put sheet metal over some of them, since there is a natural water lip over the windows, there was never any water issues. For the front of the sheet metal, side closest to the front, I used some folded over sheet metal to stop the wind and rain from getting in there when driving. Next time I would just use some carpet edging/door transition material and seal it with some sort of sealant for added precautions.

When I lived in BC, there was a fellow who had bought a Diesel, mine was propane powered, he converted it to run on veggie oil. Stopped all along the transcanada Hwy getting free used cooking oil and rendered it in the back of the bus or in a small trailer he carried behind, sorry long time can't remember that good. Thinking back on it, he said it either cost him $100 or $150 to travel from Ontario to BC that way for fuel cost. There are some diesel engine boards where they talk of adding on another tank and filter, run the bus or truck on diesel to get it going and warm up then switch it over to diesel. At night you switch it over from biofuel to diesel and let it run for about 15 minutes, to clear the way of the thicker oil then it starts easy in the morning.

There are a few sites online, google school bus conversions, some are just astounding in their complexity and work and some are the redneck slap together, hunt cabin design. Take your pick or do both!

Heating, I would now go with a propane heater, say an Olympian Wave, then build a Rocket Mass Heater in the back. Make the mass your couch or bed. If you have the time and want to go through the effort, I would remove all the metal panels after removing the seats, remove the crappy insulation and replace it with Durofoam. The Durofoam is dense shiny one side Styrofoam. It is great if there is moisture as it will not Mold like regular insulation will. In my camper now, the Durofoam is the actual insulation as well as walls. I put them in between the ribs, used metal tape to seal. The ribs do sweat a bit right now, so will be adding another layer of the Durofoam over it and sealing it all that way. I like the reflection of the material and it reflects the light as well as the heat. On of my walls that separates the back from the front is a room divider from an office, it will be going soon. Even thought it is insulated the metal in it holds the heat so it is always colder to the touch than the Durofoam, even though the panel is covered in material.

Put a regular shower stall in there, while moving or at night it can hold plastic totes, move to have a shower, or incorporate it into the Lou as well. (Lou sounds nicer than toilet) Even the regular portable hide a Lous can go in there, remove when having a shower or leave them in as they are sealed plastic anyways. For the shower I just use a 3 gallon sprayer, keep it simple, heat up water, mix to temp in the pump up sprayer. Pump it up you have lots of pressure, no electricity or complicated systems to figure out.

Some of the newer school buses have higher ceilings, so you could put the Durofoam on the floor, then cover it with a layer of plywood. Where you have your heater, put cement slabs under there, just use concrete patio stones, those big thick slabs, then put some stones ontop of them. Perhaps put the Durock under of the concrete, then stones, put Durock behind and beside the rocket mass heater and propane stove.

In my camper I put the propane heater in an older Kerosen Heater cabinet, cleared out the metal put it in there, put a roast pan on top of the metal, over the heat and put a mass in it. Now I am using 1/2 the amount of propane over last year, without the cabinet and mass to help absorb the heat and well to make it safer as well!
hope it helps.

I lived in one for years. The only problem with them is deterioration of parts wile sitting. Repairs are expensive because it requires a heavy duty mechanic. Commercial vehicles are ment to be run almost every day. The frame and engine are fantastic though. There are not cheap ones out our way though. We are looking for them to use as storm proof greenhouses.