Yes, I was thinking along similar lines IIUC of a sort of federated search using common db schemas and search apis so that I could crawl pages and they could be

Yes, I was thinking along similar lines IIUC of a sort of federated search using common db schemas and search apis so that I could crawl pages and they could be dragged in to your SERP by a meta-search engine. I think the main thing you lose is popularity and ranking from other people's past searches - that could be built in but it relies on trusting the individual indices, which would be distributed and so could be modified to fake popularity or return results that were not wanted (though then one could just cut off that part of one's search network).