If you're thinking of models the size of an E/A0 drawing or similar then it might get pretty expensive.
I was thinking that if I was going to print a landscape elevation model to cover a desktop that I'd slice the model into 7x7 inch sections (my printer can do up to 8x8x8 inches) and print them separately. Then I'd number them as they printed, and assembly the lot of 'em on top of a suitable board, perhaps with a dab of glue at each seam.
The way I'm picturing these things, I bet I could make a pretty big landscape (lets say 3 feet by 5 feet) for less than $50 in plastic, but it'd probably take a week for me to print 'em all given only evenings and weekends to work on it.