I agree the SD1 is undoubtedly the most interesting of the competition at this time, (in a near comparable price range) and provides a entirely different 'flavour' to the kn which would complement rather well, and provides an exitement factor missing from the other competition.

It has its own operating foibles, and the needs of the performer are different to those of the home player, but that is the one I would look at as a second keyboard while waiting to see what the 7k and tyros come up with.