NGINX and keepalives to backend

I wonder when NGINX will have keepalive connections to backend? Patch by Maxim Dounin was floating around for about half a year, then it made into beta, but it's still in beta now, while our media frontend server is busy creating/destroying several thousands of connections to backends instead of reusing existing ones, there are only about 20 connections needed to serve ~3.5kreq/s (current load). Well, maybe G-WAN will be better, although AFAIK it doesn't come with a prebuilt proxy caching.