Actually, the 7600 and 9600 replacements are out now. I have a 9600 using ultrachrome inks and it is one great machine!! Of course the old adage still holds: garbage in, garbage out. If your system isn't properly calibrated and if you don't have really good ICC profiles for the printer then you will be dissapointed in what comes out of printer.
I just printed a 20x30 piece on canvas for a customer and it came out great! I'm using the printing as an addition to my framing business and it is starting to take off. I had 5 pieces this week alone.
Honestly, if you can afford it, go for the 7600 (7800) as it will print 24" wide from a roll and you can get hyper accurate ICC profiles for it which aren't available for the smaller printers.
Plus, the bigger printer allows you to batch images together into one printing session rather than one at a time.
Actually, the price difference between the 2400 and the 7600/7800 is alot more than minimal. The 2400 is around $850 and the 7800 is around $3,000. Plus the cartridges cost alot more also. It seems the 2400 takes the really small cartridges while the 7800 takes the really big ones.
You will be buying the small cartridges ALOT more than the big ones. It may seem like alot more money to start with but in the long run it will be well worth the extra expense to go to the larger machine.