Have you considered splitting up your dedicated machine with a hypervisor (e.g. Xen) into a bunch of smaller VMs ?
The minimum would be 2 CPUs for each BBB process so the main process has 1 CPU and there is another one for converting things etc
The Hypervisor itself needs a CPU.
So on a 16 core system you could run 7 BBB instances x 2 CPUs = 14 CPUs and then 1 more for the Hypervisor and 1 free for a VM to play with.
If you app allows horizontal scaling then you can spread those rooms over the 7 servers.
Once you want more you can then either add another dedicated server, set up the same Xen hypervisor on it, and keep adding small VMs that each hold not that many rooms and users, but they aren't influenced by 'too many users' that could lead to higher latency etc.
My 2 cents.