i don't know, i think he'd have to change the entire concept of the list in order to squeeze vargheists in. is it stands right now, its more of a tank that lumbers forward under the protection of the engines and uses massed poison, regen, and the vampires to win the grind (or so i envision, ignore me if this isn't how the list works!). if he adds vargheists, it will be a small-ish unit for war machine hunting and flanking support, not really something i'd entrust to a frenzied, low LD (7 maybe?) unit. and if you use a decent sized unit, they're going to want to be flying around smashing stuff, not tethered to a mortis engine regen bubble. not sure how well it would work, but yes it would be insanely cool. i'm really loving the possibilities that the new book has given to feral themed strigoi armies like josh's.