This is a picture of the Forgeworld Sisters of Battle Repressor that I took at the recent Bristol Conflict event.
Though I do like the Witch Hunters army concept, as I still have quite a bit of work to do on my Daemonhunters army before I even start on a Witch Hunters army. Having said that I have always thought the Repressor is a really nice model and would make a decent transport for Inquisitorial Stormtroopers.
If I do get a Repressor I would probably add extra armour, but use homemade armour using mesh rather than the Forgeworld armour kits.
Also Forgeworld do make nice Inquisitorial doors for the Rhino which would work well on the Repressor.