I'd like to see info relating to the economics of printing yourself.
I'd also be interested in seeing comparisons between the output from a professional lab printer held against whichever model being tested.
Just as you are eminently consistent with your test shots it would be great to have consistency with the scanned printouts.
A bit tough though as camera, lens, printout, scan and PC monitor all get in between what you see and what we see.
As such, it would also be great to hear/see you describe how you perceive the differences and the quality - building some evaluative commentary on top of whichever test results and other findings you may have. You do this too for the other gear here - but maybe this particular topic can encourage more of it.
Looking forward to read your critical mind and eyes applied to photo printers