OK, here's a little update. Last night I profiled a client's Epson 3000... a kind of cute, but mildly annoying printer, especially for printing CDs and fine art paper, what with the dumb and needlessly repetitive loading procedures.
As you probably know if you have one of these, you print to disks using the "Epson Print CD" utility, which is astoundingly basic. I have no idea what, if anything, it's doing with color management, but I couldn't find any color controls to shut off or anything else for that matter. I printed a test target unprofiled, and the good news is that it didn't do too badly right out of the box.
I built a profile using the RGB targets, straight through the EPCD utility, then took my test chart and opened it in Photoshop. I then did a "Convert to Profile" and saved it with the embedded profile. It printed through EPCD with slightly better rendering of the reds and oranges, but there wasn't a significant difference.
There are four settings, basically high and low quality for PK and MK inks, and I didn't have time to try out all four...
Anyway, bottom line, it was a slight improvement, but maybe not worth the effort for most photographic printing. We've seen on the thermal printers, though, that the profiles make a big difference when there's a gradient color, so maybe this would help the inkjets there, too... I'd love to hear some reports if you give it a try since I don't have one of these printers on hand.