Windows 8.1 Bing is only free for shipping on tablets with less than 9" screens.8.1 with bing costs the manufacturer nothing as there are no licensing fees for it,so they can turn out cheap laptops etc and dont have to pay anything to microsoft
Microsoft charge a licencing fee for Windows on an HTPC.
Many of the new Intel Z3735F mini-HTPCs are shipping with the tablet version of Windows. A prime example is the Pipo X7. These installations of Windows are likely to be deactivated by Microsoft and there will be problems down the line with updates+support.
As far as I know only the Mele PCG03 and the MiniX Z64 ship with a proper Windows licence. Hence their price being higher.
I'd also add that the Pipo X7 overheats. It's ventilation is insufficient. This is why new stock is delayed.