Is Mac Mini Server feasible for a 20 person setup?

Hello,

I am wondering how feasible it would be to use the new Mac Mini as a server for a small/medium office of 20 people. The Mac Mini would run OS X Server 10.6 Snow Leopard.

Is this unit powerful enough to support 20 people? This is the setup i was thinking:

Mac mini with Snow Leopard Server - 2.66GHz : Dual 500GB:
1st Internal drive - OS only
2nd Internal drive - OS backup via CarbonCopyCloner
Ministack USB drive - Data backup via Time Machine
Firewire DroboPro - Client Time Machine Backups via the Network.

Would the Mac Mini be powerfull enough to support normal OS X Server services, and at the same time act as a client Time-Machine backup via the network?

Thanks for the information,
-Michael