Since GW hasn't made Inquisitor models in quite some time, I decided to see if any proxies have been made.
So far I have come across 2 really good candidates.
Papah-Minis has an excellent Tau Alien type proxy called the Alien Commander 2.0. Obviously a ton of work was put into this model and from the looks there are a ton of options you can choose from.
You can email firstname.lastname@example.org to get all the info.
For those who love Squats, Sciborminiatures.com has some fantastic looking Ogres that are dead ringers for Squats. They even have power fists. With a little conversion you can even add a beard to these figures and you are good to go.
Ulrik von Octoberfest is a 28mm scale resin miniature. Height from Feet to Eyes: 51mm, total height with base 74mm.