Hi Folks,
The Epson P800 has nine tanks (oneupmanship!) including a _matte black_ ink tank, and an eight channel printhead. Resolution is up to 2880 x 1400 dpi, so I can't see how there could be a problem printing sharp lines.
Not double sided, but unless the OP tells us more about his budget, one could always print the other side manually like we plebeians do.
Not an advertisement, purely for reference:
The above is based on my belief that the requirement for a PostScript only printer is a furphy. I am willing to be enlightened!
Andrew