Don't know if you'd be interested or how good it is, but I found this and it looks stable:
libev
Benchmarks against libevent 2 are rather interesting (sorry so big, but this site uses 'bb' code and it doesn't seem to allow one to size down an image like html does...
The Great thing about it -- it has a 'libevent' compatibility mode... that's almost as fast...
Have too look at the graphs a bit... but the per/loop processing time libevent2 (slightly slower than libevent), was 2.5-3x slower..
Performance improvement opportunity?
Re: Performance improvement opportunity?
These graphs show promising improvement possibilities indeed. However, I could not find any license statement in a quick scan of schmorp.de. This means in many countries this code could suffer from the no-license license. This means it should be regarded as research material only. The original writer can slap on any license later on, even commercial ones. I do believe it is just an omission on the writer's part. I will contact him to make it LGPL, MIT BSD, ... whatever. As long as he makes it clear.
Re: Performance improvement opportunity?
It was clear, just had to read the LICENSE file from the source itself. 
