Actually, with one exception, the only unlocked multiplier chips Intel makes are expensive "Extreme Edition" ones. This practice has dates back a few years, I think the first such chip was either a Pentium 4 or Pentium D.
The one exception is the Core i7 875K (I think it is called) which was designed to compete with the fact that AMD's top end chips are about $200-300, which allow overclockers that extra freedom without having to re-mortgage their house or whatever.
Some could say that this shows that AMD can't compete with Intel's top end. I would say that AMD has no interest in doing so because only nutjobs buy $1,000 consumer desktop CPUs anyway.
And qualify "meant to be overclocked". I'm pretty sure they tell you that you void your warranty if you fry the chip (although, in reality, they have no way of knowing if a chip has been fried by overclocking). So, I dont see how "You can overclock at your own risk" is any different to "Dont overclock, but here's all the prerequiste tools". Q6600 much?