According to this Microsoft KB, KMS does not require the SID to be changed, just the CMID. And this VMware documentation states that QuickPrep uses KMS to activate Win 7 desktops.
Let me know if you've found documentation that states otherwise as we just moved from sysprep to quickprep and my machines are activating just fine. I'm not any additional quickprep scripts either. Plus, we have another group running an almost 1000 desktop deployment using quickprep w/ KMS keys.