Hello all! I'm excited to have found this site, and looking forward to talking amongst this (what seems awesome already) community!
I WAS very far along, about 2 months, into the planning stage of a modernized 22' tiny house on wheels (THOW) before I came across school bus conversions.

I am now fully dedicated to the skoolie and I'm starting almost from scratch on my plans.
With the bus plan, I now have WAY more interior space, AND I won't have to trade my car in to buy a truck which will be nice. Not to mention the overall construction will be drastically cheaper.
Basically, I will be keeping my utilities the same, and will be redoing the entire layout and wall structure.
For some reason, I can't upload my photos. I'll work on that.
My tiny house plans included:
A decent size solar array and battery bank for all electrical needs. I plan on being 100% off the grid, with the option to tie in, or utilize a generator if needed, so the extra roof space is a huge plus, not to mention interior space. Not only do I want to be off grid, I don't want to sacrifice any of the luxuries I have in my house and use every day. We plan on living in the bus long term so comfort is key.
Propane for cooking & hot water and that's it. I want running water, so store and pump is seeming like the best option and I already have my entire plumbing systems' components figured out.
Composting toilet so no black water tank. (read the Humanure Handbook by Joseph Jenkins. It's worth the read, I got mine on amazon used for $0.01 with free 2 day prime shipping)
A Passive (HRV) Heat Recovery Ventilation system which requires very little electrical energy will keep humidity levels where they should be and keep the interior air clean and at a comfortable temperature. Including the stove exhaust and the bathroom exhaust fan, there will be a total of 4 fans making up the air system as of now. This might change as I get further into my skoolie design.
I have plans for a large bathroom and kitchen space. I was a chef for a long time so kitchen is important to me. I had no idea how cheap you can buy buses. The tiny house trailers I was looking at alone are $3k plus brand new.

I'm already considering raising the roof (guess it's time to learn how to weld), luckily my father in law is a retired master welder/teacher for Mitsubishi. Only problem is, he's moving to Texas in two weeks and he's busy with the move so I guess I'm on my own.
I am still trying to figure out what kind of bus to get, any input would be very much appreciated. I intend on living on the bus full-time and traveling a lot. Under carriage storage would be ideal for water tanks and battery storage to keep the center of gravity low. For Florida, where would be a good place to start looking for buses? I would imagine Disney or Universal has tons of retired shuttles that might be worth investigating. There's also lots of schools. Is there an end-all directory I should know about? I am not against driving to pick a bus up.
What would you all recommend?
How do the plans sound so far?
Any questions? I've got tons more ideas and information, and a 1:12 scale foam board model, and a few 3D renderings I've made using SketchUp but it won't allow me to upload any photos for some reason.
I could go on all day, sorry for such a long post!
Looking forward to talking with you all, Thanks in advance!