Sadly, I don't think there's a lot of nude beaches in Sweden.. to find the few that I guess must excist (must be somewhere), I think you'll have to dig hard.. ;P I might be all wrong though, it's just that I've never really heard of any famous nude beaches.. (though I haven't been looking). The gay saunas don't excist in Sweden from what I know though, I mean.. there's gyms/saunas that has a lot of gay visitors or may be "famous" to have a lot of gay clientel (or however you spell it), but no out-spoking "gay saunas" I think.
Hope you find some. :) Or just throw your clothes and create your own nude spaces, haha!
EDIT: Oh, and I'm so jealous! Australia is my top place to visit! Why someone wants to come to Sweden for vacation is beyond me though, atleast if you're from a place that seems so great as Australia. ;p