My next warband Idea was the warband of my next Inquisitor, Ostrek Tannenburg. My plan was make him a radical, with an Imperial guardsman, a pathfinder and a rogue trader in the style of Indiana Jones. Are there any specific radical philosophies i.e. Xanthite for Ordo Xeno Inquisitors who hire Xeno to their cause.
How can an Inquisitor be a Rogue Trader?
As for a "radical xenos philosophy", you could of course use the typical radical philosophies, such as Istvaanianism. The Dark Heresy books have put together a faction known as the "Xenos Hybris" [link] (http://wh40k.lexicanum.com/wiki/Xenos_Hybris) - though it's said to be confined to the Calixian Sector. You could easily come up with your own philosophy - it's easy enough to do. A "faction" need not be as large or as wide-spread as Amalathianism to be a "faction". Groups of Inquisitors who hold a similar point of view are all you need to form the nucleus of a "faction".
An inquisitor doesn't even need to be part of a faction. It can just be what he thinks ont he subject, and he'll be darned if anyone can convince him otherwise!
Many Inquisitors are considered "free agents" and aren;t ties to a particular ordo or faction.
Plus, factiosn are just arbitrary categories provide to help us as a player. Most Inquisitor probably don't go aroudn labeling themselves. Instead, they just do what they think needs to be done. The labelling is most likely done by peers and observers, not the Inquisitor themselves.
I could see Istvaanian radicalism being used in that manner. Perhaps an Istvaanian inquisitor would encourage war between certain human planets/populations and an alien species. If he were to have Xenos in his warband or entourage, maybe they would be co-conspirators, who have a similar philosophy and encourage this method (maybe even secretly believing their race will win).
Of course it is always possible to have an inquisitor who believes that aliens can be useful, they can't be trusted but it is better if they die than when humans die. It would also be possible that he believes that xenos technology can be more useful in some regards than human tools, for that reason he uses them.
if you are interested, here is a link to my thread about my xenos inquisitor and his views and beliefs. his background is the last post. maybe the comments in this thread left by other members can give you some advice/info as they did me...
http://www.the-conclave.co.uk/forum/index.php?topic=1648.0