uhm. the themes have some sort of relation to one or more of Nifflas' games, and fitting colour schemes. Even if someone made a theme somewhat "light red or pink", I wouldn't really see a reason to include it. There are a lot of downloadable/installable/usable themes on the smf support/modification/plugin site, but those don't relate to Nifflas, which is pretty much why they aren't used. I'd say.
So, even if/when another forum layout theme would be made (*whistles innocently because of knowing
nothing), it'd have to do with what Nifflas does : his games- to get a chance to become selectable. Or his music, but I doubt anybody can make a "Niffmusic-style"-theme.
If you absolutely can't bear the forum style, there was some firefox extension that allows a lot of customization how websites you visit are supposed to look like. Something with a monkey in the name... sorry, too drowsy to remember the exact name. google it if you want.