Link to video:
All credit for this build goes to Desolacer and k1ckd0wn for their inspiring speed rifting spec: http://www.diablofans.com/builds/3299-speedrifting-desolacers-armageddon-dh-build
Playstyle: You keep Vault pressed all the time. Hit Chakram about once a minute to refresh, and just hit all the other skills constantly as they're simple cooldown skills (you can optimize it by alternating Vengeance and Preparation so that you never run out of hatred and so on... but most of the time you'll want to focus on the bounty itself and can't really pay that much attention to hatred management). Given enough CDR/RCR you'll never have any hatred issues and be able to continuously Vault around the map. No speed limits! See video above.
Still working on it - leave comments if you have ideas for improvements.