Your best bet is an NEC ELITE IPK (Usually comes with cabinet,cpu, and 8 port esi card as a package)and add a 8 port c.o. card for lines.The system can be programmed from any extension or you can obtain the IPK Sat software for your computer.

Could you give me a price range -- looking to spend under 2,000 used

THANKS

I think if you are not into the latest gears, then you should be able to pick-up a used KSU for the Elite 48 (which will support upto to 12 outside line and 36 stations (or is it 16 and 32?)  Either way, it's way over what you are expecting to use.  Anticipate paying 'bout 600-700 for your KSU and about $50 / phoneset.

Drawback on this though is that you may need help installing this whole setup, and it's also a pretty basic setup without voicemail.  Another drawback is that you may need to upgrade the ROM version to get some of the later functionalities.  Watch for lowered pricing in the near future since Elite 48 is "discontinued" from NEC, and lots of people are clearing them out. (For the extra $100 or so, you should go for the IPK series KSU, since they are expandable, and that's still current products from NEC.)

Good luck