Like Pulp miniatures, the problem with basing Inquisitor warbands is that they rarely stick to the same sort of terrain. With pulp games figures move quickly from city to jungle to desert, and back to the city, and likewise in Inquisitor games one could move from Hive to Underhive to a verdant crop world, or an ice world. Bases can already look a bit strange when they match the terrain, and having the figure drag a circle of city around the desert can look even more odd.
One solution to this problem is to either base in just black, or possibly even with clear bases, the idea being that very little attention is paid to the base, and more to the figure and the game. This method does pose problems for the other 99% of the time, when your figures are not involved in a game, and are either in a display case or exist merely as pictures online.
So it probably makes sense to just base the best you can, with the most common sort of terrain you plan to play on, and just live with it. In my case, since I am also (very slowly) working on Necromunda figures, it makes sense to base Inquisitor figures in a like manner, which is to say a modified Underhive sort of look, with broken terrain bits, some sand, and minimal plant life.
|Something like this bounty hunter figure (old)|
Basing III - has a useful method for making multi figure bases.
And for something completely different, Orlygg has an old-school basing tutorial.