If you want to go bigger (and with more light) I would recommand to not use a RGB led but a white led with a colour wheel this is because a bigger led has more room between the light point and colours do not mix that well (also use glass optics, for this design I use a frosted plastic lens, this does mix the colour good but gives a wash like beam. With clear plastic lenses the colours do not mix properly). Also I would add gobos (with rotation) and a prism.
Next it would be better to also use stepper motor instead of servos (for larger and quieter movement). I'm currently working on a version 2 with stepper motors and could keep you updated on the progress.
Also I would make the casing not from 3d printed parts from laser cut aluminium sheet metal.