TV Mounting Dilemma

Hi All-  I'm looking to mount 3 Panasonic TC-P65VT60 Plasmas left to right on an  basement wall (outside wall, drywall w concrete block behind). I have 3 Sanus BLF-213 full motion mounts, as these are the only units I can find that support the oddly wide VESA pattern of the Pannys. the TVs weigh about 100 lbs each, and the mount is about 55 lbs (crazy I know) . The issue I have is the studs in the basement wall are turned sideways, meaning behind the dry wall there is only .75" or so of depth, then there is concrete block (appears they may not have even used 2X4s) . I called SANUS and they don't support an install of this type as they say it has to go either through 3.5" of wood, or directly into the concrete/ brick. Given the weight of the TVs and mount, I'm unsure of the best path forward, or whether any companies who make mounts support these types of installs. I don't plan to pull the middle tv off the wall pretty much ever, and the side TVs would only be pulled out occasionally for certain situations, so the extra forces pull down should be pretty minimal. I'm wondering if it's possible to drill through the 1.5 inches of wood and into the concrete block, and install some kind of hybrid? I think straight downward force would probably be ok but still concerned whether when pulling out or turning the TV that could potentially be dangerous.

Does anyone have experience with these types of situations, or know a company whose mounts support this type of install?