The main microcontroller however will need some kind of interface, but I couldn't really figure out what I would like to have for this. One option will be a box with some sliders, buttons, and a nice display, but in the meantime I wanted to try to use an old gamecube controller to control the lights!
Luckily someone wrote a very detailed article about the communication protocol of the controllers, which someone else used to write an arduino program that converts gamecube controller signals to N64 signals. With the arduino program as starting point I could easily read the 12 buttons and 6 potentiometers (2 joysticks and the L and R buttons) from the controller, and control an rgb led with it.
When I receive the rf transceivers I'll see whether it works nicely to control multiple lights with the controller, or that a box with some buttons and a display would be better. If the previous is the case, I'll buy myself a wireless gamecube controller as a remote control for all my projects!