I've had the 7800 for about a month and it's amazing. No more headaches trying to tile films with halftones and textures. Keep an eye on Craigslist, sometimes people have trouble selling them locally so you can find a good deal. I used that search tempest site where you can check a bunch of different cities within a certain radius at the same time. I had to drive 4 hours to Charlotte for mine but was able to grab it for $350.
I'm using rolls, yes. I get my rolls from lex-jet, but I think there are some cheaper options out there. Also you can keep a lookout for the 9800 as well. It's a bigger machine but you could print your films out 2-up. If you find one and the price is right that is.