Here's something to think about. With an 8x10 camera, you can use: Wholeplate (6 1/2"x 8 1/2"), 5x7, and 4x5. On many cameras you can use divider boards, for instance to make 2x 4"x10" or 2x 5"x8" per sheet with an 8x10.
Originally Posted by puketronic
The 4x5 Deardorff Special is actually a 5x7 camera with a 4x5 back, and virtually any other 5x7 can be fitted with a 4x5 back.
Don't waste too much time and energy analysing which camera to buy as your first LF camera, there's a very high likelyhood that as you get off the toe of the learning curve, you'll want something different from your first choice.