Please stop being worried about an single entity having 50%+ of the network,
Someone could have 90% hashrate and as long as he doesn't mess with the chain rules you've nothing to worry about.
We do have something to worry about because such a scenario would undermine Bitcoin as a currency. Thus, great care is taken to avoid it.
ASICMiner can avoid this in many ways, and I trust friedcat to manage this strategy however makes sense.
.b