Well to be honest, I was thinking about the types of solutions that it would take a geek to dream up The kind of geek who thinks about graph theory and topology and dreams of images like this one:
http://www.wired.com/wp-content/uploads/blogs/wiredenterprise/wp-content/uploads/2013/10/graph-hires1.png

So the geek imagines that each dot in the above image is a full node in the bitcoin network. Each node has the choice: either 1) to decide for himself or herself which version of the bitcoin client to implement, or 2) to leave that decision up to other nodes in the network who have more time to think about these things, and whose judgement you trust. For example, I might decide that I want to run whichever version that Jeff Garzik decides to run; or maybe I'll decide to run whichever version is run by a majority of [Jeff, Risto, Andreas, Gavin, and my friend the bitcoin enthusiast down the street]. Maybe I'll give two votes to Gavin, half to the guy down the street. All that would be represented on the graph by five directed arrows (of varying thickness) from my node to each of the 5 nodes controlled by those 5 people. You could always change the settings in real time. That way, if I read in the news that the Chinese this morning unleashed a surprise 51% attack, and their plan included capturing Andreas and forcing him to run the version of their choosing, then I and everyone else in the world (everyone who is following the news) could instantly remove his node from the list of trusted nodes. My girlfriend might decide that she doesn't feel like keeping track of all these crazy bitcoin personalities but she trusts me to do so, so she just programs her node to implement whichever version I implement.

The point of all this is to come up with a system such that:
- consensus is derived in a transparent fashion; it is clear who the decision makers are at any given point in time
- it does not require everyone to be paying attention; therefore does not require a crisis for changes to be made
- can implement minor changes in which only the major players are focusing their attention
- can implement major changes in which everyone is paying attention
- consensus can change quickly or slowly; either way, the decision process is transparent

Incidentally, a system similar to the above could be used to exclude nodes that were suspected of participating in a 51% attack. You would effectively end up with two big networks that were walled off from one another, e.g. one run by GHash and one run by everybody else. The world at large would follow the one not run by GHash so it wouldn't matter if they had 51% or 99%; they would be ignored by everyone.

This making any sense?