I think that West Wind may produce some, too, although their hairstyles aren't very modern-looking.
(South) East Asian head sprues do represent a gap in the market, though, especially with respect to ancient times and tribal peoples.
Moreover, it would be nice if somebody were to produce sprues of helmeted heads for all of those bare-headed Chinese figures that were inspired by the Terracotta Army. Helmets have been found, albeit made of stone scales or lamellae, but it would seem likely that actual soldiers would have worn ones that were made of lacquered leather and/or of bronze.