My biggest concern with doing something like that would be how efficient it is compared to using the native interface (and why I said you'd need to redesign the kernel, so that it could be implemented efficiently), the only benchmark you have is vs. poll() (and uses ab) ... which is pretty sad.
epoll <=> kqueue is probably the best case test too, to be convincing you'd want something that benchmarked EVFILT_VNODE/SIGNAL/TIMER at least. To be really convincing you'd want PROC/USER/AIO and play with the EV_* flags.