Wrt to luke-jr's attack it wasn't this. He simply had the difficulty shoot up, and then left, leaving the altcoin issuing one block every X days, rendering it pretty much unusable.
Perhaps we're discussing different altcoins that Luke-jr has attacked. He did 51% CoiledCoin using hashrate from Eligius to merge-mine CoiledCoin without the knowledge of the miners using his pool, and minted blocks with no transactions. Perhaps the high-difficulty stranding you're referring to was a different alt.