They had the white one a coupple of month ago.
Some people protect the spacebar by applying translucent scotch tape on it, I personally find it ugly.
It takes ages before your spacebar looks like mine, so don't worry and if it someday look similar to mine all other caps probbably developed a good amount of shine as well.
I think you can always buy a new set of caps, for such a great keyboard it will totally worth it.
I woudn't recommend to get a full set of caps from EK, they are way to expensive! I'd buy it directly from Japan!
In case you don't have a proxy in Japan, tenso.com is a nice service to get the stuff you want
Anyway, don't waste your time worrying to much about the spacebar, it is meant to be used!