Well, after four years of heavy use, my primary Epson 9900 printer seems to have given up with a head failure. I'm still working on trying to fix it, but the problem was sufficiently bad that I've added a new printer to the stable, the new Epson P9000.
Besides the roll holder cover at the top being black, it is pretty similar physically to its predecessor, and I've started testing now to see if Epson's claims about improved performance and reliability are evident. So far, so good. As for the two partially broken 9900's, I have not yet decided their fate -- they may go back into service as Piezography printers or they may retire gracefully.