But again, the interesting thing is that you can buy up 51% of a PoS coin, and then sell off your coins so that you no longer have 51%, but your history of having once owned 51% makes it possible to attack the network at any time, for free.
I doubt it.
Doubt all you want, the math doesn't lie.
Of course I was somewhat wrong by stating "for free" -- there would be *some* computing resources involved (and thus electricity costs, etc.), but nothing close to what 51% attacking a PoW coin would require. Several orders of magnitude difference.
If you once had a 51% stake, you can build a better blockchain than the other 49% can, starting from the point where you owned 51%. You develop this blockchain in secret, after selling off your coins (and profiting from it); and then release your secret blockchain to the world, and nodes will pick it up because it carries more stake than the 49% blockchain. Now not only do you have your profit from the original sales of the coin, you have your 51% back (to the extent that it's worth anything). All coins would not have to be consolidated under one address; in fact, I believe that doing so would prevent the attack in most PoS implementations.
This is a fundamental problem with PoS, and is why Peercoin incorporates both PoW and centralized checkpointing. Sunny King is not a stupid guy, he knows that PoS has a big flaw or else he would have implemented pure PoS for Peercoin.
(f*king fiat snail currency) 
.. I dont mind about LTCRabbit and Multipool.us, as they pay in LTC and BTC respectively.
