Multiquoting would take up way too much space, so I'll try and address some of the topics in the past 5 or 6 posts.
Regarding <20Hz content in movies, there is most definitely content in those ranges, especially in newer releases with the lossless tracks. Please do not take offense to this comment. In no way am I trying to say that any of you aren't experts in your fields (especially Dennis, who is regarded as one of the best in the world). However, I typically watch action flicks like Transformers, Black Hawk Down, How to Train Your Dragon, etc. If you're interested, there's a thread with a large collection of movies and waterfall graphs showing the frequencies of the soundtracks. Most of these have content to about 15Hz, many are below 10Hz. http://www.avsforum.com/t/755493/the-master-list-of-dvd-hd-dvd-blu-ray-movies-with-bass-thread-with-waterfalls
For that reason, I'll be installing a rotary sub or two to play as loud as is necessary to reproduce those sounds. Music won't be listened to very much in the theater as we will have a multi-zone sound system for the rest of the house. However, taking what you have recommended, I should just forget about trying to isolate so low. I am open to the idea of hiring an acoustic engineer, such as Dennis or Ted, to design the room. However, I don't want to do so if we'll isolate down to a frequency that I could have designed myself. So, Dennis and Ted, what is a reasonable frequency to isolate to, knowing that I'll be watching these sorts of mega-bass movies?
Regarding my actual speakers setup, it is as follows: JBL 3731 >80Hz> 2x JBL 4645C >20Hz> Rotary Sub. I've got lots of experience with building and designing speakers, so this setup may change, but I think I'll keep it where it's at for now. This setup sounds incredible and is significantly less expensive than most commercial models advertised for home theater (85dB sensitivity for a $17k speaker? Give me a break!). I'm aiming for reference level audio at all frequencies. This shouldn't be difficult at all for these speakers in a smaller room.
So, let's add a couple building restraints so you guys can have a better idea of what's realistic for me to expect. Let's assume I go with the best materials out there (QuietRock 545?), I don't want the gap between the two rooms to be more than 12" (not including drywall, just the physical gap), and that I have the option of using concrete wherever you recommend, what do you think is a reasonable go to set for isolation at reference levels? And, let's assume we significantly reduce the internal ambient noise of the system, thus making it not necessary to play as loud and therefore not requiring as high an STC rating.
Thanks again for all your help, I really do enjoy learning and hearing from the experts.