I created a simple proof of concept in Go that does what I think you're after. I was looking for feedback on this list a little while back but it was around the time the list servers were down so I imagine the message got lost in the shuffle. Primarily I was looking for information about (a) interest (b) feasibility (c) gotchas / security issues to be aware of.
https://gist.github.com/cameronjacobson/5c19fbeb64610b39e3e6 The only difference is the code here is a whitelist. It should be relatively straightforward to convert it into a blacklist though. The code is rough and unpolished, and not commented so apologies for that as well. There are of course other alternatives, but my feeling is for what I'm trying to do, it's a little overkill to install a full featured proxy server that in some smaller deployments will simply sit on the same server as the CouchDB server. And that has alot of features I'm not going to be using and can at times be a pain (ie. overhead) to try to administer or configure correctly.
