<p>I'm using KVM to run a Windows virtual machine on my Linux box. Networking is accomplished through a tap device, hooked into a bridged Ethernet device, which allows the Windows VM to basically appear like a separate physical computer on my network. This is pretty nice.</p>

<p>However, my understanding is that most, if not all, wireless drivers can't support bridging. I'd really like to be able to roam a little more freely while I'm working -- does anyone know of an effective workaround?</p>

<p>User-mode networking won't work, as I have to use some Windows VPN software that wants lower-level networking access.</p>

I assume that you could configure your Windows guest to use the host as its default gateway, and set up NAT via the wireless interface on the host. So the signal flow would look like this:
Windows software opens connections to a host on the internets.
Windows routes the packet via the default gateway, i.e. the host Linux system.
Linux does NAT magic and routes the packet via its normal routing table (which should use a default gateway via the wireless interface).
I have never tried this in combination with bridging though.