PVM in Germany does classic rims, too. Though their webpage only list the front rim in 17 and 16,5", they do any size on request:
http://www.pvm.de/de/raeder/5-speichen-schmiederad-neo-klassik-vorderrad/
http://www.pvm.de/de/raeder/5-speichen-schmiederad-neo-klassik-hinterrad/
Friend of mine bought a pair and got it individually lightened, too, for his 500 Laverda project bike. very, very light rims, but in standard- trim not lighter than the GSX-R rims I think.