Glad to see someone else suggested dragonheart - that guy that slagged em off was clearly talking out of his arse and probably a slipknot fan.
I thought Maiden were too big, and cradle would be veryu good indeed
A couple of other possibilities though
Christian Death
Intense
Stampin' Ground (they put on one hell of a live act, but the problem is they might attract too many nu-metal/hardcore fans...still, you the promoters need not concern yourselves with my hatred)