If you wanna borrow from old gang verbage, you can call me girl, I suppose. Like "whaddup, girl" or babe is nice too. Like... Maybe call me something sexy and degrade me, don't nullify me by making me into a man. I would rather be a sex toy, a literal object, than be a man.
Dunno, I use "dudette" pretty frequently with my girl friends (and I don't mean Egg Carriers™, nor do I have something better than "girl friends" - initially wanted to go for "chick pals" as a snappy equivalent, then I started feeling like That One Creepy Uncle). Actually use "dudette" more than I do "dude," it has a nicer sound to it.
As I see it, "dude" is gender neutral when used as an interjection, same as "man" and "guy."