I don't know if you are interested. But for proof prints, I am running OCP Claria Match Dye inks on an older Epson 7600.
I have been quite happy with the quality of the output, and how well they matched my final Epson K3 output. I was shooting mostly 4"x5", and smaller prints just didn't represent what was in the image.
The 7600 was the last printer that allowed you to reset all of the values manually, and to access all of the maintenance panels. I run one as a proof printer with the dyes, and one as a B&W printer with custom mixed B&W inks, along the lines of Paul Roarks inks.
I just ordered new dye inks today. The cost averages to about $20 for 1 quart - 32 oz. The total cost for a 220 ml cart comes to $4.65 per 220 ml, or about $.02 per ml.
I bought the printer itself years ago for $500. The older 7600 is not as efficient as the newer printers. I will have to recalculate the actual amount based on the ink used, as I have the ink counter turned off. You could pick up a cheap 7800 or 7880 to do the same thing - I have had the 7600's for many years.
My standard proof print for 4x5 is 24"x30". For my 1DsII it is 18"x27". I like to proof a lot of images large, as the final destination is a large print. Hard to get the same feel at a smaller size. I have a Nikon 800E on order and will also proof those large.
For proofs I use Epson Premium Semi-Gloss 170 because of the light weight and relatively low cost. I stocked up when Epson had a buy 2, get 1 free sale. I think my price was about $.20 per sq ft for media.