I want to be able to have VM names like Fedora 10 Windows XP FreeBSD 7.2 but virt-manager won't let me. Is there any good reason for that? Even if there's something in the system that can't deal with filenames with spaces, it could still allow spaces in the UI...
Doesn't seem to be a reason - libvirt allows it
I think the original motivation is that xen denies it: that is at least the case for xen in RHEL5 it seems. We could make this hypervisor dependent behind the scenes, but it sucks to have to make such a distinction when validating a name.
IMHO not allowing special characters in the name is a feature. If we want to have human readable names, we should introduce a new field in the XML for storing this.
Okay, that sounds like a WONTFIX