I was just looking at the auction place and got myself a protar with three elements. Sounds like it goes from 10 inch to 27 1/8 (254 - 690).
I've seen these with 4 elements, sounds like mine comes with 3. (16, 19 and 27).
Should be fun. Good news bad news. The bad news is that I paid a lot for it, the good news is that it came with an 8x10 Deardorff (may need new bellows, recommendations?). Keeping my fingers cossed that everything is in good condition.