It might be less that it's VM aware but instead is BIOS aware, as your hibernation error indicates. So the system knows the BIOS does not support ACPI, therefore it doesn't bother with the settings.
I'd guess that you'd be able to push these settings out to the real clients assuming their BIOS/UEFI does support it.
Something I've noticed with XP, the power savings settings are unique to each user who logs in. So if you set the system to not sleep at all, then logged in as a different user, the default settings would take affect for the new user.
In this case pushing out setting via GPO is best.
I'm not sure if this applies to Windows 7, we haven't had as many people roaming from computer to computer on Windows 7. FYI, I'm not using roaming profiles.
If for whatever reason you can't or don't want to push out GPOs, you might look at Sysprep options and see if you can set these there. Normally I'd suggest using the 'CopyProfile' option, but as I found out yesterday, it just does not work!
Assuming you follow all the rules regarding CopyProfile, (don't join the domain with the original setup, only have one active account on the computer) MS still doesn't fix the registry fully. I found that the Citrix client under my new profiles was pointing to the originally created profile and I could only imagine what other things in the HKCU key are still pointing to the original profile and not the current one.