First, does Cisco ASAv has integrated with Sourcefire/FirePower? If not yet, will there be any plan?
Second, what is the difference between ASAv and ASA 1000v?
Your requirements will guide you to one set of solutions or another. Your local Cisco account team or partners in your area should be able to guide you with some whiteboard sessions to flesh out the most appropriate solution set.
Meanwhile, have you looked at the Cisco Secure Data Center Solution guides? I'd especially recommend a close look at "Secure Data Center for Enterprise — Threat Management with NextGen IPS Design Guide", just published in August 2014.