I yielded to temptation over the holidays and bought an Epson Pro 3800, mainly because I was using the R2400 reasonably heavily, and I got tired of changing the ink cartridges.
The 3800 ink cartridges hold about 10 times as much ink as the R2400's (but they only cost 4 to 5 times as much). Same ink, except that the 3800 holds 9 cartridges (Photo and Matte Black at the same time) - it still has a changeover, but it wastes very little ink to switch between Photo and Matte Blacks.
The 3800 will print A2 (double the size of A3, which is the limit of the R2400 and R1800). However, it won't do roll-feed, so the R2400 wins for that.
The quality of the output from the 3800 is very high (better, to my eyes, than the R2400, but the difference isn't too obvious). Unless your lab is using black magic (or should that be black black black magic?), they are unlikely to beat this.
Oh, and the 3800 has two interfaces: USB (like the R2400 and R1800), and Ethernet - you can use it as a network printer without needing a server - that's rather nice if you have multiple Photoshop machines.
Haven't had a glitch yet, and I've printed 30+ A4s, a handful of A3s, and one A2.
Oh, and it's only about 40% more than the R2400...
they say you have to take a thousand bad photos before you can take a good one - I have mastered the bad photos part...