IF you want an overall similar colour look to all surfaces Epson will be your best bet.
Notice I didn't say the best printer as this is simply not possible to say. As you have researched the differences show the lighter gamut being larger and more saturated in the top end but rightfully so lesser in the shadows Epson K3 are a good compromise considering Epson do well on all paper types, glossy being only surpassed by HP for gloss diff with GE. Just remember that if you want to switch media often, it will cost you a lot compared to Canon and HP.
HP on any media other than relatively uncoated cotton rag has a good gamut, and a very good gamut on any photo type media . Glossy canvas should have an extended red gamut similar to other photo media.
IF there is one area that HP have done well is with Canvas according to artists and photographers reports. If true, combined with overall media range and the extended primaries, the HP still has polyvalent capabilities worth looking at. The repeatability is guaranteed with the onboard spectro by way of Auto closed loop calibrations, so your prints and reprints will always have very high proximity of colours that no other printer will have. Something print makers have always wanted now made easy.
Thanks very much for the input, Neil. I recognize that I would prefer the extended light gamut saturation of both the HP and Canon printers, but am as yet unable to determine if I can live with the reduction in dark-gamut saturation that I would experience with those two printers, given that my work contains a lot more of that type of color than traditional photography.
Obviously, I'm talking about a subjective judgment on my part, so I realize that this is a difficult question for someone to help me with. But, without actually printing my work on all 3 options, it's a difficult call, so I figure that even speculative input is better than basing a $5000 purchase on guesswork.
Essentially, based on everything that I've read. I'm trying to imagine my work with an extended light gamut and a slightly truncated dark gamut. Of course, trying to visualize such a thing accurately is probably folly, which is probably why I'm stalled in my decision-making process. Still, I have to try to figure this out prior to purchasing a 44" printer.
What it comes down to is that I would prefer the extended light gamut, if I could live with the reduction in dark gamut saturation. How I will make this determination without actually seeing my work printed on glossy canvas with a Z or ipF printer I really am not sure. I received a couple of canvas samples from HP, but these were far from conclusive and were also on matte, not glossy, canvas.
(BTW, HP also sent the print of one of your B&W images on Hahnemuhle. Nice photo, and the ink/paper combination was very appealing. Makes me almost wish I was still into doing B&W fine art photography, it looked so nice... but, I've definitely moved on to less-traditional realms for good.)
Thanks again and Kind Regards,