I'm not entirely sure what you mean by "mirrored HSG80 controllers". If you mean two controllers in one enclosure, this is a normal configuration called a controller pair. You can run a two node cluster attached to the controller pair. However, a given LUN is only active on one controller at a time, so you'd have to use multiple LUNs (which is probably what you want to do anyway) to load balance between the controllers.
/charles