Err i think they stack but not sure. Watched a vid i think Britteny posted and i think NVB and berserk stack, and since all inspiration is is a lazy copy and paste of Bloodlust* with no special qualities of its own, i'm guessing yea.
Inspiration has no damage component to it, so yes they stack. Neo and weapon proc powers stack last I checked, but that was over a year ago so I don't know if they patched that out or not.