Searching for a long range suspended ceiling system

I am trying to conceive a 'box in a box' system, and i am stuck at the ceiling step.The room is 4.70mx9.75mx3m I have the choice between a regular suspended tile ceiling, with as much as silentblock as needed (but it will be rather expensive as per the number of silentblocks), and a system that may lie mainly on the wall sides. A friend of mine talked to me about Megastil/Stillprim systems from BPBplaco,http://produits-btp.batiproduits.com/Placo/Megastil-plafond/fiche/r?id=1000209417 saying it was used in big recording studios and cinemas, but there may be other solutions. The principle is getting a big range (in my case 4.70m at less), so that the ceiling doen't have to be suspended at many points. Does anyone ever used that kind of systems?