Intel Developer forum has a presentation on a fanless small form factor design based on the next Atom processor.
Seems like you could have a fanless Atom Server.
And, there is a session on Windows Home Server built on Intel Atom.
Designing a World Class Windows* Home Server using Intel® Atom™ Processors
In this session...
• Receive a detailed understanding of the Windows* Home Server logo requirements and Consumer Storage Platform features
• Learn about Intel Storage Group’s next generation Intel® Atom™ Processor based platform
• Understand how additional platform features like Storage BIOS, drivers, and system software help OEMs quickly launch a state-of-art system
• Review the Intel® Storage Small Form Factor motherboard specification
• Take a detailed walk through the Intel Storage Small Form Factor reference system to understand the various design decisions and how Storage Group’s platform technologies make this an excellent Consumer Home Server design
• Walk through the various ways to extend the Windows Home Server platform with software add-ins