Supernode (>full node security) for large merchants and miners

[dree12]

With the recent blockchain fork, people have been forced on edge. One of the earliest pools to discover the problem was the Eligius mining pool, thanks to running simultaneously 0.6 and 0.8. To help avoid these problems in the future, I propose that large merchants and miners use a "supernode" similar to Eligius's setup. They would run more than one version, and if they ever disagreed immediately shut down all mining or payment processing. These supernodes would cost marginally more than full nodes to run, and would help improve network security greatly.