Whats the name of a BMW iDrive type of encoder?
I don't have an iDrive, but it looks like the 6DoF sensor on the 3D Connexion Space Pilot device. Most everyone who uses Altium seriously has at least one of these things- they're complementary with a mouse or trackball. 

The cheapest one was only about $75 last time I bought one- the fancier ones are around $400 (the main difference is the presence of an LCD display and programmable keys on the Pro versions).  



"3Dconnexion patented six-degrees-of-freedom (6DoF) sensor"

Here is a teardown of the SpaceNavigator (cheap version) in German. 

They don't have switches, all 6 degrees of freedom are proportional (analog).