screen is now complete and mounted on the media unit! Sadly I don't really have that many photos of the build process, but for those who are considering a similar build, I'm more than willing to answer any questions you may have. It took the better part of yesterday with the help of one other person for most of the process. It's one of those things that has a bit of a learning curve; if I were to do it again, I could probably do it in half the time (with better results). For those of you questioning a DIY build because you're unsure of your skills, it's really not that bad at all. Plus it only cost ~$250 CAD (if you're in the US, you have much better access to supplies, so I imagine it would cost much less) compared to the $500-$600 average I saw online for a tensioned screen (non-AT!). I don't really consider myself much of a carpenter, but if you have basic woodworking knowledge, it's fairly straight-forward -- take the plunge, it's really quite rewarding when you're done (and I haven't even setup my PJ yet!).
So final dimensions are 107" by 60". I had to reduce the height of the screen from my original 67" target because the media unit I bought wouldn't allow for anything taller to be mounted due to my low ceiling. I think 13" less inches on the width is better in the long run anyway, since I have more room to place speakers, etc. (the ones in the photo are there temporarily to test my new NR818 AVR =D).
Frame pieces before assembly:
Closeup of frame pieces before assembly:
Rear view of assembled frame with spandex on:
Mounted on the stand:
I have to get some blackout material for the window behind the screen (even with the shutters closed, any amount of light shining on to the back of the screen makes the center braces clearly visible), and also for the top shelf of the media unit, which is black glass and highly reflective. Also, I WILL be putting a 1.5" or 2" black frame around the screen at some point in the future despite me saying recently that I would not... there are 4 problem areas in the corners of the screen that will create low-points and certainly drive me nuts. This was a poor design choice (using the steel studs without spending the time/effort to do 45's for the corners, or at least putting something in the gaps to make it flush) and now I have to live with it.
Anyways, if anyone is still interested in this thread, let me know if you think a "lessons learned" would be helpful!