GW says your wrong
Chaos FAQ: "Models armed with a bloodfeeder can exceed 10 attacks. Is this allowed?
A: Yes, as they are bonus attacks that only apply in that combat turn, and do not permenately modify the model's attack characteristic."
[url]http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1610178_Chaos_Space_Marines_FAQ_2008-05_Edition.pdf[/url]
I agree with Chumabalaya. I like special characters, they just need to stop making the characters effect the list layout.
Oh, and Kharne gets 6 attacks (he has a plasma pistol). That's 7 on the charge. Between the fact that he hits on 2's and wounds on 2's (on the charge), and that he doesn't have an 11/36 chance of taking an auto wound AND doing absolutely nothing that round of combat, I'd pick him over a lord with bloodfeeder.
Bloodfeeder's average number of attacks is 11 (on the charge). 3's to hit, 4's to wound means he'll put 3.666 wounds on a MEQ squad on the charge.
Kharne gets 7 attacks on the charge, hitting on 2's, wounding on 2's. That's 4.86111 wounds on a MEQ squad, on the charge. He will also, statistically, cause .97 wounds on a friendly model.
If the Bloodfeeder lord even does anything at all, he has to roll very well in order to beat out Kharne. Just don't keep friendly units close to Kharne, and you're ok.
Oh, and Kharne gets 2d6 armor penetration. Bloodfeeder doesn't. Kharne laughs at Dreadnoughts, Bloodfeeder lords cry.