Howdy Eric, I am not sure a vacuum system is all that important in a school setting. There are many less expensive ways to secure the material to the table. In a production environment vacuum is just wonderful, but then the bot is run by someone who uses it all day every day. Students are another matter.. The bot will be misused not by malice but from the learning process.
I would invest in a very good dust collector if you don't have one already. As much as possible use metal ducting with flex hose only where necessary. That ground all the duct-work to remove static. That will probably be the best investment for reliability. Its also nice to touch a hose without that static zap.
There are other people using Bots in school settings, I expect you could call the folks at Durham and they would probably get you some contact info.
Good luck-
D
"The best thing about building something new is either you succeed or learn something. Its a win-win situation."
--Greg Westbrook