I don't think this rumored house has anything to with Havok. Every year, it's pretty common for people to link symbols on the spec map to previous houses, even though most originals we get aren't sequels. It's not uncommon for some to hold onto the early ideas from spec, even if new rumors go against them.
What you're describing here is probably far enough removed from Havoc that it should probably be its own thing. While Havoc is remembered fondly by some, I don't necessarily think it's iconic enough that most would recognize it if it came back, especially in such a different form.