3TOP,
Hola! Almost every manufacturer has a factory course that will teach you special tecniques and specific knowledge about the aircraft they make. You can even arrange "special" courses with most of them.
If you want to "explore the edge" I would suggest that you look into the National Test Pilot School at Mojave. They offer a Rotary Wing Short Course for a reasonable price that teaches you aerodynamics of test, test techniques, and the reasons why things are the way they are. You will fly in one or more aircraft but more importantly you will learn more about your aircraft in a few weeks than most people learn in a lifetime. Shawn Coyle or Mike Hardey are both instructors at the school a PPrune members. Check it out, you won't be disappointed!
Adios amigo. Que la vaya bien.