The purchase is just for expansion. The older 747-300 are not to be replaced for a while. First up for replacement are the MD-11's. (still an interesting question...) But also not on short term. A Dutch newspaper was mentioning the Airbus family, but I guess they have the same resources like we do. It's all speculation. The only thing certain is the purchase of 4 747-400's. Period. The rest is gossip.
That guy with a dad working for KLM is me!!
Even KLM-personnel doesn't know about KLM's airplane strategy. The 747-400 order came unannounced, like all the other KLM orders as the 737-800 and -900. They're very good at keeping it a secret until the last minute. It's just a simple 'wait and see' case with KLM.