Just past an industrial area in Mound House - through the gate displaying a sign warning visitors if sexual activity offends them, then turn back now - sits an unimpressive white building.Cathouse or haunted house? The sign only warns visitors of one. Behind the doors of the BunnyRanch the working girls tell tales that have attracted the attention of paranormal experts and ghost hunters, not just lonely guys hunting for a good time.The stories are told by several prostitutes. Publicity stunt or not, they are convinced something strange is going on at the BunnyRanch. This week the SciFi Channel's "Proof …