I have a very dominant male in my tank and any male that comes in knows right away who's boss. I find male guppies can get aggressive, especially when they get older(my most mature male is the dominant one who bullies the teenager males). I've never had any really bad attacks between my males, but to lesson the stress between the less dominant males, a female distracts males from picking on one each other so i would advise having females too. This is just my experience with guppies, but i've heard some people dont have problems with all male tanks. Maybe if you bought a bunch of young males together, then maybe it wont be as bad.
Is it that you dont want alot of babies or that females aren't as fancy looking as the males?