I wouldn't call it a "good" fallback, but i do have a VPS handy with an always-on squid proxy (remember to bind only on localhost and use via ssh tunnel, or some other secure method, if anyone is going to get ideas from this comment) among the other things i use my VPS for.
I do find that different subsets of services tend to get blacklisted.
Ah damn. I was hoping that would be a good fallback.