Absolutely. IMO the thing to model them after would be the PIM (personal information manager) pseudo-computers of the early 1990s. Segmented or possibly coarse dot matrix LCD (2-4 lines, ~40 characters), and a special (read: charity) deal with a chip manufacturer for a modest but modern microcontroller, such as an Atmel AVR32, which Digikey has at unit prices around $7. Bulk pricing for a large order of these direct from the manufacturer might be drastically cheaper (~$5? $3, even?)
They'll run linux, but I'm not sure how to get networking into them. Wireless might be a bit ambitious (802.11 is clearly out of the question). Maybe with a simple GPIO pin you could control a small AM transmitter/receiver pair, with the intent of transmitting ~300bps. For the money it might make sense to just put a couple external metal contacts on it and run wires to each desk -- which would also solve powering it.
They'll run linux, but I'm not sure how to get networking into them. Wireless might be a bit ambitious (802.11 is clearly out of the question). Maybe with a simple GPIO pin you could control a small AM transmitter/receiver pair, with the intent of transmitting ~300bps. For the money it might make sense to just put a couple external metal contacts on it and run wires to each desk -- which would also solve powering it.