That's cool. I use the 9800 and love it. Epsons K3 inks are the most archival ink set on the market. Make sure that if the printer is set up for dyes or pigments that you stick with the ink set it's dedicated to. I'm assuming this is an option for the 4800.
Also stick with the Epson inks. Don't go to a second party's inks they're never worth the trouble they cause.
In my experience i am going to have to disagree. I picked up an epson 3000 off the side of the street, i bought a cleaning cartridge for about 29 bucks and then 3 black cartridges for 24 bucks total. I couldn't be happier with the films i get out of this thing. I guess if you are willing to run through cleaning and purging cycles for about an hour then its not a bad deal.
they might be a bit on the pricey side, and it sucks that you can only get them in packs of 100, but really, i never thought i could get such good ink output on film with my printer (tried others in the past with no success). i don't know what kind of ink the cartridges for your epson uses, but i think they make them for both dye-based and pigment-based ink carts.
EDIT: btw, 17" wide...that's fucking hott. also, i don't know if it has top feed-rollers, but if it doesn't, you might be able to get this film instead: Standard Inkjet Positive R-Film
you might want to ask for samples of both. this place is really cool about sending samples, and they're quick about it too.