Coffee Appreciation

My new boss has asked me for advice about getting an espresso machine for the office we're going to move in to. I suggested a proper commercial machine may be overkill but he doesn't think so. Plumbing in won't be a problem.
I was thinking of a 1 group machine, maybe a Rocket rotary one, but I'm really not sure.
Where's best to find second hand commercial machines and grinders?
Anyone got any ideas?

That would be awesome but my worry would be:

Takes a lot longer to make coffee
Having to train people/have 20 odd people messing about with an expensive machine, could prove to be more hassle/cost than it's worth...

But hey, it's his cash, right?!