Well let me start by asking, how do you plan on running your Ordo Xenos =][=, wargear wise?
Do you plan on running him in carapace armor, or power armor? What weapons & equipment do you like or plan on running?
I for one use the Inquisitor model below, Inquisitor Lorr, as a basis for my Ordo Xenos inquisitor.
I used this model as a base, and after a minor accident with the miniature (dropped it and the pointing finger broke off the right hand) I opted to do a weapon swap and plugged a bolt pistol in on the arm instead. He's painted up to gel a little better with a Deathwatch Killteam color wise, and overall I'm very happy with him and often use him as my Ordo Xenos =][=, Inquisitor Atticus Garrow.
If you're wanting power armor (not a bad call, honestly, as 3+ save does not ever suck in my opinion), you'll be better off either converting one up in plastic using marine bits, or
If you're looking for a more standard model without having to do a ton of conversion work, then either of these models will likely fit your bill. The first one could have either power or carapace armor, with the robes he's wearing you could get away with either option visually.
Or for a more dedicated carapace armor version:
Those are the ones I would recommend. I'm currently going to be building an Ordo Hereticus =][= in power armor that I will use as a dedicated anti-psyker type inquisitor. My Ordo Xenos =][= is almost always run as a psyker (Prescience is so very good) so having a Psyker inquisitor and a anti-psyker inquisitor lets me have my options open and enjoy some nice flexibility.
I hope that helps you, and do please keep us informed on your progress.
Take it easy
-Red__Thirst-
More than 7pts, less than 7000...just 
4000+ 
2500 
2000+
