JR Inkjet are selling something they call
CISS (Continuous Ink Supply System).
"It is the means of supplying a continuous flow of ink to the print head of the printer without the need to change cartridges.
Large external ink reservoirs continually supply the cartridges with ink through silicon feed tubes. The cartridges remain in place permanently in the printer. The ink reservoirs are independently separated by colors that can be easily refilled only the empty tank anytime. It works efficiently in almost all brands and model of printers."
Looks like an interesting idea - anyone tried it?