Dual Thunderbolt displays with a Mac running Windows under Boot Camp?
Unfortunately, as of now, you are unable to (I'm assuming that this is what you mean) daisy-chain two or more Thunderbolt displays (natively) into your Mac. I'm unsure if it's Apple to blame, Microsoft, or both. Wait until Windows PCs start receiving Thunderbolt (Microsoft should update the drivers by then) and try again. If that's not it, then it's probably Apple's fault and there is nothing that you can do now until Apple updates the Boot Camp drivers so that it can support this.