Re: Bus Search
Most buses were built in a variety of lengths to accommodate school district requirements. This includes the P30 models. There are also different window sizes - Blue Bird uses 28" and 35" body sections and Thomas uses 28.75" and 38.75" (measured between the centers of the posts between windows). You may find 5, 6, or 7 window versions of the P30s (maybe even 8, I don't know much about the options on those). Short conventionals are slightly more common, and most bodies are available as short as 5 windows.
Wish I could help with dealers, but I'm in the US. You could try calling around to a few local school districts and ask how they dispose of old buses.