Pyromancer (Demolisher+Occultist) is what you need.
Despite being nerfed in 1.0.0.5, it is still a pretty solid build, and without doubt, the best for dual-wield.
Guides to that build are in this thread, on 1-st page. Dont be so lazy, and find them.
Oh, and it fits “demon hunter” theme wery well (cause uses occultist class).
Agreed. I play a pyromancer and have a pretty solid dual pistol chaos/fire setup with procs everywhere, a pet, thermite mines and blackwater cocktails in addition to a fire strike setup.