Sir, I salute you. Go Khorne! All Khorne! Nothing but Khorne!
Anyway...
A greater brass scorpion is one of these
It's a super heavy vehicle, and as such is only game-legal in Apocalypse. It is also a very expensive piece of kit (altho its a big bugger, which kinda justifies it. See the bottom left pic in the set of 9 for comparison)
If I played Khorne, I would buy one, cos it's cool.
A Blood-slaughterer is one of these:
a good deal cheaper than a BScorp, and also legal in games of regular 40k. However, because it's a forgeworld model, there are a lot of tournaments that dont allow its use. For day-to-day use, though, most people are fine with it. I use my blight drone all the time when I play my stinkies.
While we're on the subject of FW, if you play Khorne, are this and this not utterly tempting? (despite the price...) Heck, I want to buy the Bthirster and I dont even play Khorne! Its just so, ultimately "rraaaaaaaaaaaaargh!"
aces!
ps the rules for all these bad boys are in Imperial Armour Apocalypse 2
or you could go the Evil and Bad torrent route. Not that I'd know anything about that.

pps - that uber bloodthirster can be used as a regular 'thirster, or as ChompyTeeth The Special (or whatever he's called) which is a special super-heavy daemon for apoc games. He costs 888 points and Kicks Ass...