This has all been done many times before, there is a search, use it, and if you want more information, "The Titanium" had really really nice "team blocktress" server a while ago.
EDIT: thanks to (extremely annoying) v11, shape base name datablocks fail, so there is no way of easily doing the cloaking, although i was messing arround with greekbots (because i wanted to see if it was any good) and i saw that i could create a bot, (no name) and control it, and with ffc, make it invis. So it is possible to make a spy cloaker, the only thing is, what happens to you while you "become" a bot.
he had a load of custom scripts, not just a build, he made some tf2 addons just for his server and did not release them (i think it was before the tf2 pack was started)