Might I suggest '-dono'.
It's very similar to '-sama'... but used to be used for the Emperor.
However, it's used far less in modern days...
I became infatuated with it after watching Rurouni Kenshin, in which he called respected girls with '-dono'...
So now I use it much like '-sama' for girls. =P
Generally... I'll use '-sama' for mods, or people I really respect... (Ancient members... Ken-sama, Kei-sama, Style-sama, BobCat-sama)
And I use '-dono' for girls I respect. (Mutsumi-dono, Motoko-dono, Eva-dono, Chao-dono, Pariah-dono)
-taicho can also be used...
It means something like "Captian". Use it for Brigade leaders.