VirtualBox has support for VDE since version 3.2.0. We should have a USE flag for it, that will just pull in net-misc/vde as a runtime dependency.
As long as net-misc/vde is installed, the "Attached to:" drop-down will have "VDE Adapter" as an option.
Created attachment 274567 [details]
diff to add the USE flag
I can confirm this works for me. Please add the use flag.
I don't see any "VDE Adapter" entry in the aforementioned drop-down menu after installing net-misc/vde. Even recompiling virtualbox with --enable-vde didn't change anything.
Created attachment 351304 [details]
VDE network configuration as of version 4.2.12
The configuration screen has changed slightly from the time when the bug was created.
Relevant information from http://www.virtualbox.org/manual/ch06.html:
> VDE is available on Linux and FreeBSD hosts only. It is only available if the VDE software and the VDE plugin library from the VirtualSquare project are installed on the host system