Just an idea but with the keyboard being as modular and replaceable as it is would it be possible for either framework or someone else to make keyboards with different colored keycaps, ie red, blue, pink. Similar to what is done with the bezels.
You could do it, with some work. Framework says the keycaps are not meant to be replaceable but at least one person has been successful in rearranging theirs without breaking the clips.
You could have new keycaps 3d printed in any color you want. Would have to create models for keys first, I don’t think anyone has done that yet. Keys that still allow the backlight to shine through the letters would be really expensive to have made, or hard to DIY.
Iirc Framework showed off a potential RGB backlight option for the Framework-16. Would be easier to just go with that, when it’s available.