Stoyan has an interesting post about two new methods for IPC. The MCIPC (Morse Code IPC) uses one mutex and the well-known morse code. The other method uses 64 mutexes (+1 for silence or bus tact) to form 64-bit bus.
I'll have to spend some time to implement the 64-bit bus and see how fast it would be. Of course, to make it really useful, I'll need to implement bus controller and mechanism for interrupting and getting ownership, so that multiple processes could use the same "bus". Otherwise I'll run out of system resources quickly if I run more than two processes. :-)