I've recently gotten an idea for a DE Kabal with special rules... like +1 to cover saves and the ability to infiltrate or hidden deployment given to basic troops (or as wargear?), and perhaps some bonuses to Mandrakes (9" move?). There could be severe limitations on vehicles to balance it out... some sort of fluff regarding their tendency to lie in wait for their foes, and ambush them suddenly and without warning. The Kabal would probably also lose its Piratical Raiders trait, since they could theoretically as well as attack - and likely draw defenders out from a base to ambush, rather than perform a traditional raid. (or as a distraction... maybe when they are the attackers, all foes must make an automatic move towards them, before play begins?)
Hmm... ideas...
...comments/suggestions/flames?
--Pyronate