Well, I'm not a designer, but they should know who to contact. I have some of the KDE devs on G+, although not the designers. It will be an interesting direction, but the road will be paved with obstacles since lot of the people who use KDE like to be able to tweak it as much as possible. It's hard to do a design that incorporates all the tweaks and still remain simplistic. But if they manage it, that is going to be a great coup for design in general and something everyone can learn from.