Ian
Do a ebay search for "CIS" or "continous ink systems"
both those will pull up many different items.
even spotted a cis for cannon printer.
Epson are diffent then HP or Lexmark cause Epson has the printhead in the printer, whilst HP and Lexmark have the printhead on the cartridge.
Thats why HP and Lex are dearer and their sales pitch is every time you put a new cartridge in you get anew print head.
The printhead in the Epson though is more robust and loner lasting.