libusbK is a complete driver/library solution for vendor class usb device interfaces. If you are a usb developers or usb device manufacturer seeking a driver solution for a new USB widget then libusbK could be for you.
https://github.com/mcuee/libusbk/
http://sourceforge.net/projects/libusbk/
http://libusbk.sourceforge.net/UsbK3/usbk_about.html
http://libusbk.sourceforge.net/UsbK3/index.html
Dual license with New BSD option and GPL option. This should make it easier to facilitate different use cases.
Many examples are provided for the library users to develop their own applications. https://github.com/mcuee/libusbk/tree/master/libusbK/examples