Maybe instead of failing silently, the browser should cease to function at all if it can't reach its OCSP data source for a public CA, and complain loudly - providing we can make revocation lookups cheap and highly available.
It could be available via anycast akin to DNS, or p2p as gojomo suggests. Lots of places use DNS to operate blacklist/RBLs - some with very large datasets which would break the internet if they ever become unavailable.
One idea/question, is there a way to add to the feed via an external URL, rather then exclusively within the Chrome plugin?
I would use it even more if I wasn't constrained to chrome.
For example, adding this little snippet as a bookmark would for certain work from Firefox and iOS/Safari, and quite possibly others.
If I could get it molded to work with your service I'd be pretty stoked.