It's fairly easy. Just create however many subsites that you need and set the permissions to unique rather than inherited on each one. If you're planning a large or complex site arrangement for each department, you might want to go with site collections rather than sites. HTH

on item #2 - note that rebuild times are inversely related to the number of drives. The more drives that you have, the quicker that you can rebuild one from parity. I think about it this way: if I have two drives, each is 1/2 of the data. If I have three, then 1/3. If four, 1/4, etc.

Well, I'm glad to hear that. I know so many people who get stuck in a job that they hate, and are unable to leave. It's nice to hear that there are some who manage to turn things around and come out on top. Good luck!

Sounds like it's time to look for a new job.

Or you could do it in English (UK) using a Do Whilst loop... :-D