They are up and basically done. Thanks to all for your help... especially Ethan and Bryan. Glenn, too. All of you have contributed to my knowledge and I appreciate it. My dad and wife also helped with the installation and fabrication... it would have been very difficult without them.
Here are some pics of what has gone on. Please ignore the need for touch up paint... as well as the water spots on my camera. I threw in a little something extra at the end for fun.

Front left... note the opening to the rest of the house.

Front right... note the IB subwoofer above the TV!!!

View towards the rear of the room... note the lovely bass traps

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Framing of 1st reflection panels for the right and left wall. All first reflection panels have 2" 3# unfaced rigid fiberglass panels... this and the following two photos were taken before the rigid fiberglass was installed.

Framing of 1st reflection panels for the front wall.

Framing of 1st reflection panel for the ceiling cloud.

Front left. The fiberglass panels within the 1st reflection absorber are about 4" out from the wall.

Close up of the upper front left corner (above the opening)... note the truncated vertical cross corner bass trap. It is 6" thick 8# mineral wool.

Font wall of the theater... note the horizontal cross corner traps and IB centered above the TV. The wall is bare in the middle in anticipation of getting a front projector and screen. The horizontal cross corner traps have two 12" wide and one 8" wide 2" thick 3# rigid fiberglass panels laminated together (for a total thickness of 6") and the one facing into the room has a kraft/foil skim on it.

The ceiling cloud... note that it is hung by i and j bolts screwed into the rafters and the framing of the absorber. The fiberglass panels are about 5" off the ceiling.

Close up of the IB... it has two opposing Ascendant Audio Avalanche 18" subs. This is obviously a shot of one of the drivers... getting a shot with both in view (and dicernable) is very difficult.

A cross sectional view of how the horizontal cross corner traps are attached. I'll be sure to cover up the ends... I just wanted to leave it open to take photos and show how they were attached.

Right wall.

Right rear view (when facing the TV)... note the bass trap along the rear wall behind the couch. It is spaced 1' off the wall and is 6" thick 8# mineral wool.

Left rear view. Note the prominant vertical cross corner bass trap. It is 6" thick 8# mineral wool.
As for the IB's output, I took some SPL measurements with the most recent digital Rat Shack SPL meter. With Sonnies corrections for this version of the meter, the results are promising. For reference, I used Ethan Winer's test tones downloaded from his website. I'm going to have to describe the plot as I don't have a working scanner and the results were manually drawn on logarithmic graph paper.
Pink noise was set to 75 dB. The in room response from the main seated position started at 77dB at 10 Hz and steadily and for the most part evenly rose to 97 dB at 37 Hz (there were a few minor blips). It then dropped to 83 dB at 46 Hz. After that it rose to 100 dB at 56Hz (and stayed there until 63Hz). From there it droped to 95 dB at 76 Hz and then rose to 99 dB at 81 Hz (and stayed there until 100 Hz). Then it slowly dropped to about 75 dB at 140 Hz.
All of this was done with the sub amp gain turned up 100% (or more accurately the attenuation set to zero). The sub output level from the integrated amp set to a point (+4). This was done because it's the maximum level I can set it to for my listening preferences (the clip light on the Samson S700 has only flickered once). I normally listen to movies with the volume on the integrated amp set at 40 (but the setup and levels are otherwise the same). In order for the pink noise to be at 75 dB I had to have the volume set to 20. Although I don't have the manual in front of me, I believe that when I set the volume to 40, the response is 20dB louder than it would be at 20. So, without EQ, I think I'm capable of 97 dB at 10 Hz! I'm sure I could turn it up even more, but I just don't like to listen that loud. BTW, the front left, center, front right and surround speakers all cross over to the sub at 80 Hz, and the sub also gets all of the LFE signal.
What I gather from this is with my new parametric EQ (Behringer DSP 1124p), I'll be able to cut significant response across the board and still be flat to 10 Hz. Moreover, I'll have room for a decent house curve and not have to worry about destroying my Avalanches by over excursion or clipping the amp. I think the null at 46 Hz most likely comes from having the IB centered right to left and having the main listening postion centered right to left. Even though there is a significant drop in SPL, it's still well above the pink noise level. It could definitely be worse. When I set up the BFD, I'll do several curves. One for center seating for music, one for center seating for movies, one for sitting a foot or so left (and right) of center for when my wife and I watch movies together. It'll take some work, but the potential is there!
And... just for a little fun, I thought I'd add this...

BTW, that is a bald man's head at the bottom of the last photo!