Microsoft has another new version of Windows coming up, but it doesn't end in the number 8. The Windows Team just released an RC of Windows Thin PC, or WinTPC, for more specific of restricted applications.
Microsoft's Karri Alexion-Tiernan blogged about some of WinTPC's virtues:
Customers like the reduced footprint of WinTPC – the machines they will likely use it on often have less disk space than brand new machines and WinTPC helps to ensure they will have adequate space. They also like the write filters which are helping customers to secure the device running WinTPC by preventing them from saving data or installing applications locally and they’re also pleased they can leverage their existing System Center products for management and deployment.
Windows Thin PC is expected to hit RTM sometime before summer.