Hi Stefan, Thank you so much!
I think in case of networking, you can expose the network facility of the guest OS, which uses the dedicated USB-Wifi card, via the virtual NIC provided by Virtualbox. The nic_router component in Genode should be able to mark the domain of your guest OS to be the uplink for other domains. With the corresponding routing rules within your guest Linux you should be able to route requests from other Genode components to the USB-Wifi card. Of course, this is a functional solution, but not a favored one with respect to minimal complexity ;-).
Indeed, I was able to get this working. I am able to write this message from within a TinyCore VM, which is connected through Sculpt to a Debian VM. It is as you say not ideal, and it takes a bit of setup, but that's partly because Debian is not configured to act as a router by default. The routing within Sculpt was not so difficult once I understood the concept that "policy" can be used in place of "uplink" and still provides network to the outside world. However, the way I made it work was to replace the /config/managed/nic_router with /config/nic_router, but it then displays only "Local" under Network in the Leitzentrale. This works for the VMs but has the side effect that the depot cannot be accessed by Sculpt. Do you know if the launcher (or whatever other part if I misunderstood) can be "fooled" into attempting to download from depot even when it thinks the connection is local?
P.S. Eventually it would be good to replace Debian with a very small VM just dedicated to the WiFi driver, can the Sculpt version of vbox or seoul run headless?
Regards, Colin