Had some fun, drew a diagram:
It shows the 2 pumps idea... which might also provide some kind of redundancy... So I might go with that. Also i'll try to make the res the highest part in the system to dual it as an airtrap. And the "eletronics" box on the diagram is going to be the most interesting

Pumps will get their power from there, and all data from the thermistors will be sent to a small microcontroler (pic or 8051, haven't made up my mind yet), which will log it and broadcast it to all the pcs. Maybe I could make it so that you have to press a button on that box to boot the pc, that would allow some extra checks, and the pcs could be powered down when the temps raise too much (either by cutting the power, or by sending a shutdown command which would be processed by a daemon)... this could be an interesting project

hmm, thinking about this, a 28 pin pic combined with 256kb or EEPROM should work fine i think...
Anyone has some comments?