The venerable Kodak 6800 and 6850 printers are true workhorses; it's not uncommon to see them flogged on eBay with upwards of 200,000 prints on them -- not because they are worn out, but because they tend to outlast the systems they're plugged into.
I originally added support for these models to Gutenprint the better part of two years ago, and through some helpful volunteers, I was able to reverse-engineer enough of the printer communications to write an open-source CUPS backend to enable them to print under Linux.
That seemed to be good enough, and I generally forgot about these models.. until a few months ago, when the folks over at LiveLink arranged to have an Kodak 6850 sent my way. (These guys are awesome, BTW!)
Having full access to one of these things made it far easier to poke and prod and generally reverse-engineer the printer communications. Consequently, I've mostly decoded the printer media status (now with print counts!) and media query messages, and greatly improved error detection and recovery.
It's probably safe to say it now works better under Linux than it ever did with the Official Windows/OSX drivers, though without access to a 5x7 conversion kit and media I'm sure there's something I've missed.
In other news, I'm still hunting down some bugs involving the Sony UP-DR200, Canon CP900, and Mitsubishi CP-D70/CP-K60 models, but with only indirect access progress is slow.
It would be so much easier if the manufacturers of these things could toss some documentation my way. It could only help them sell more printers and media, after all..
Back to the bit mines..