Rumour site FUD Zilla claims AMD's K11 processor generation may feature eight or even as much as 16 cores:
AMD K11, codenamed Bulldozer, is the chip that is scheduled for early 2009. This will be the chip that should take care of high end market and co exist with overhyped Fusion.
K11 will have 8 to 16 cores and as far as we know it will be developed in 45 nanometre, which implies that it might be quite big chip. Intel should be switching to 32 nanometre at the same time but we are not sure if AMD can keep up the shrinking game.
Doesn't sound too bad, but as always it's probably best to take these rumours with a grain of salt.