My bus is a commercial series instead of a school bus but its fiberglass cap looks similar to yours.
Unfortunately, my conversion probably wins the prize for "slowest-moving conversion that technically isn't abandoned." I did the 16" roof raise about 4 years ago, riveted on new sheet metal 2 years ago, and painted the sheet metal this summer. Been too busy to document that stunning amount of work on my build thread though..
The plan is that in the spring I'll get into fixing up my fiberglass cap. Last winter I used a snow bank to arrange a mock-up of how I hope it'll work out. You can see that there
. Hopefully next spring I'll get around to actually attempting it.