I think bringing in the different colours is a bit risky for the vendors. They tend to bring in the colours that sell. I know black is available as well. It would be nice though for variety, but in the end, popular is what sells.
I agree but I think the traction of the EGO one device as a kit has been quite good and the take up is there especially considering that Twisp is selling the same/similar device and coils are all standard.