The only combination that is possible (and by that I mean it may still not work out) is to have females co-habiting. As you said males and/or male/female combinations are not recommended.
I understand from this forum that beardies are generally solitary creatures, and although two females might cohabit successfully, there will still be dominance issues. You must also consider the space requirement for adult dragons. A single adult minimum is 40 gal, but 75 is much better. Now consider how big your tank must be for multiple dragons.
I started with one, I still have only one, and when I have more space and money then I'll expand to more, in separate tanks. Good luck in your setting up, and congratulations on choosing a really rewarding reptile.
-----
Ross
1.0 Bearded Dragon (Fuego)
2.1 Roommates (require more cleaning up after than the dragon)