I've been able to target an eBox system (3310A) from Platform Builder (in VS 2008) running on my Windows 8 system.
(PS Having a Core i7 makes build fast!)

Retail Build

It is loading via DOS/LoadCEPC and the image booted OK.
I turned off the dev machine's firewall just to be sure.

Target Control works OK.
Remote Tools seem to be OK (tried Remote File Viewer and Remote Registry .. both OK)
CerDISP worked.

Launching OS from development machine via BIOSLoader-eboot works.

So it looks like Compact 7 development on a Windows 8 system is OK except for the VM.