This is also part of the mainline Linux kernel now (look under drivers/usb/usbip/ and tools/usb/usbip/).
Last I checked, there was someone from Eltima Marketing proposing the site be updated with some revenue sharing deal to their proprietary and costly Windows and etc. USB over IP solution.
Also, there were numerous users in their forums posting signed and patched drivers for modern Windows since the ones available for download aren't signed, so I saw.