Have you thought about making a second Pi zero to act like a client, forwarding the usb/ip atach to a physical usb port on the client?

I hope this project revives the USB/IP Project. I'd like to use this for remote control of cameras for live stream and time lapse in an Open Source Film Studio - https://docs.google.com/presentation/d/1-Kwsd3S_4gD2LdPW7G7RkY3GpBdTN23PTxGbvYSk5VM/edit#slide=id.ga6a0c4e6d6_0_0

I like this project, I'm actually looking to do something related, so I thought bouncing ideas around could be useful.

From my understanding, the standard Linux usbip server is actually sufficient, if you add some udev rules to bind and unbind devices as they are plugged and removed. A simple match on the bus/port intended to be relayed should be enough, from what I can tell. The only complexity is handling the different USB standards, as USB 1 and USB 2 present as different busses. Not a big deal, of course. Advertising can probably be achieved with simple Avahi/Bonjour multicast DNS-Service Discovery advertisements.

The more interesting/difficult side is the client, I think. My requirement is for a Windows client, but the idea's should be cross platform.

I'm less concerned about a GUI and autodiscovery, and more interested in the automatic binding of devices as they are added to the server. It seems to me that once the usbip client is connected to the server, it could simply poll periodically for new or removed devices (`usbip list -r serverip -p`) and update its bindings. Is this essentially what you implemented in your client? 

When a usb device is attached a udev rule gets run, here the example of where I setup a udev monitor on the server side and the server would then go and send attached clients the message
https://github.com/dicetrash/qusbipserver/blob/master/udevmonitor.cpp#L14
There are a couple windows clients with usbip but for windows they require signed drivers so thats generally something nobody wants to sink giving microsoft their money into.
The standard usbip message protocol contains info about what standard is attached.
also yes I too chose multicast, no need for dns just general broadcast and discovery
https://github.com/dicetrash/qusbipserver/blob/master/grouplistener.cpp#L80

Thanks for the response. There are a couple of Windows clients that have got their builds signed, I think. So submitting a feature request there seems like the best approach.