Found another RC motor that can be used with LEGO: the Kittenbot Geek Servo
It works very well with my Pololu Maestro board although I just can get a little less than 180º rotation instead of 270º as the title of the product at Bangood states (to be honestly I didn’t even noticed that title until now as I expect all RC servos to rotate 180º or, when modified, to rotate continuously).
I have a fixation with small LEGO motors and this one motor is smaller than the 4DBrix motor:
Both top studs and bottom reverse-studs connect to LEGO bricks but only bottom reverse-studs give a strong LEGO-like connection. The Technic-like holes work very well and the axle is also Technic compatible.
For monorail or train rail switches I still prefer the 4DBrix Servo because I can attach it directly to the 4DBrix monorail swicthes (of course) and to my Technic-based rail switches as drop-in replacements of Power Functions M or L motors (or even MINDSTORMS EV3 smaller servo). But for my LEGO Rock Concert cameras this little fellow might do a better job. It’s still bigger than the good old LEGO 9V micro-motor but it is already geared and Technic attachable so in the end it might even save more space and give bette results.
Each kit comes with 4 motors so the price is also quite good.