VirtualBox with USB2 and USB3 support

Ever since I switched to FreeBSD I noticed that Oracle doesn't support FreeBSD when it comes to the VirtualBox Extension Pack. I'm not a C/C++ developer, but was wondering... Can one develop an open source virtualbox extension pack - or is that only something Oracle can do? The reason I'm asking is because QEMU has virtual USB 2.0/3.0 controller (EHCI/xHCI) support. So couldn't somebody with the programming skills port QEMU's implementation of the Virtual USB Controllers as a open source VirtualBox extension pack?

Just a thought.