Mary-Jo Foley posted a blog on this topic, Microsoft: Tax bills for Windows 8 gift tablet just a mistake and she posted an email address which you can email if you received the mystery 1099: nikedist@microsoft.com. Indicate “Tax Related Inquiry” in the subject line.
I sent an email and this is the response:
“We would like to assure you that what was communicated to you at the BUILD conference remains accurate. It is our intention to cover the tax obligation related to the distribution of this device. We are working quickly to resolve this issue. If you did receive an incorrect 1099 tax form, you will receive an updated version in the mail within the next couple of weeks. Please let me know if you have any additional questions.”
Just posting this here to help anyone else that received a mysterious Microsoft 1099.