Update 2, October 8, 5:00AM PDT - A Microsoft spokesperson responds:
Unfortunately, HSN made this offer without the support or authorization of Microsoft.
Microsoft and major retailers are getting ready for general availability of Windows 8 devices on 10/26 and not prior to that date. Once Microsoft learned of the HSN promotion, we contacted them and asked that they discontinue the on-air and online offer since it is not yet 10/26, the date that marks the official availability of Windows 8.
An e-mailed statement included this quote from Peter Han, Microsoft's VP, US OEM: "We are looking forward to Windows 8 General Availability on October 26, when customers can take delivery of Windows 8 PCs at retail for the first time."
The e-mail also included this quote from Scott Ledterman, Acer's VP, US Consumer: "We are excited to support Windows 8 with great Acer and Gateway offerings starting on October 26, but this HSN offer came prematurely and we've requested its immediate removal."
Update 3, 8:00 AM PDT October 8: All five products are still listed on HSN's website, but attempting to purchase one results in this message: "We're sorry, this product has sold out and is no longer available."