Tell urllib2 to use custom DNS

I'd like to tell urllib2.urlopen (or a custom opener) to use 127.0.0.1 (or ::1) to resolve addresses. I wouldn't change my /etc/resolv.conf, however.

One possible solution is to use a tool like dnspython to query addresses and httplib to build a custom url opener. I'd prefer telling urlopen to use a custom nameserver though. Any suggestions?