Hey Nick, can't comment on retract/tension type screens as you know I'm a DIY guy. Front Projection is the only way to go for true Home Theatre entertainment.
I can't recall what projector you ended up with, wasn't it the Panny 700? I luv my Z2, but am thinking about selling it to a friend and getting the Z3 that just came out...
I have heard that some of the retract, and even tension screens can over time start to show waves, not good. If I were you I would start with something in a Matte White, 1.0 gain material. One idea if your planning on painting the screen wall white anyway, would be to figure out where the screen will display on the wall, and don't apply any texture to that area or use semigloss. When your not watching a movie, most people may not even notice the area. Another option, I just came across at Menards in the paneling aisle is Parkland Durotherm Lite panels. They have a matte white side and are about 1/8-1/4" thick, so they would not require any backing, and are very very light, so you could remove it from the wall if you wanted. They come in 4 x 8 sheets. If you want 16:9, you would have to cut the length down to 85" and you'd have a 98" diag. Or you could leave it alone and you'd have a 2.0:1 screen for 107" diag. I'm planning on a 2.05:1 screen of 54" x 110" constant height setup. This allows me to enjoy the wider formats like 2.35 material and use the full height of my screen, of course I have to adjust my zoom when watching 1.33, 1.78, and 1.85 material.
good luck
