Getting back to the subject of the OP here. I have limited knowledge of printing, from my P800 I print a maximum size of 17x25" prints, however, it is my direct experience that seeing them printed vastly complicates the thinking process behind editing. There is a completely different process for editing for a certain type of medium - and most editing these days is done for the digital medium.
To me you mentioned that the printers are discontinued, however, it is my understanding that you can and will still be able to get ink for the printers for many years to come. To me this is an opportunity to get a good printer, that still produces high quality, at a discount relative to what it might have cost if it was still in production, and you shouldn't hesitate to just purchase one and use it for the purpose in which you need. Perhaps afterwards you trade out of it, and get something that is newly released after they've worked out some of the bugs.
I would also suggest picking up a P800 like I have, with the same color spectrum at as the larger version, this will allow you to print "crops" on a 8x12 on the same paper, and proof your larger prints easily without having to hassle with that beast of a thing. I picked my P800 up for $300 on craiglist, and the ink is $65/cartridge. Every time I print a 17x25 it costs about $10 with paper and ink costs. But I cannot tell you how satisfying it is to see these high quality prints up close. Even if it's not particularly profitable.
