presented me with the answer with the flower shaped Aquarelle palette he designed.
This palette is intended to encourage his students to work with a limited palette of 12 colours and to mix them on the paper rather than in the palette, so there is no 'mixing' space.
They hold up to approximately 2 full pans of paint, can keep paint moist, keep paints covered when not in use and are neat and portable. Perfect!
I don't use them for doing a regular painting. I have set up many of them with my extra pigments - colours that are perfect for a particular painting for me or for my students; pigments that are really granulating; primatek colours etc. It may be possible to mix the colour, but the properties make them useful and can't be created by mixing others. They contain many cadmium colours that I use to demonstrate opacity or for special effects in a painting.
I set them up using one for yellows, another with yellow earths. A third has oranges, another has reds, purples, blues, greens and so on. It makes it much easier to find a pigment or colour in a demonstration or while painting.