It's not that hard to write a webcam kernel extension now, apple iirc provide a sample (but I think I based mine off someone else's implementation for passing buffers around to the sink)

Here's mine, turning a kinect1's depth stream into a camera device

https://github.com/NewChromantics/PopKinectMacWebcam

So in this case, the hack is unneccessary, there is no limit of which you speak