h/t kicks condor
Okay I'm like one of the probably-fewer-than-ten people in the world with a defined whostyle, so obviously I'm psyched by this.
Having a list of people (defined by h-cards) and an offline tool to traverse their sites, grab the whostyles, sanitize the CSS, rescope the selectors, and repackage for your own site seems like a totally valid approach to me. That way the sanitizing could improve over time without having to respec inter-site dynamic inclusion.
If you wanted to be properly agnostic about it, I'm sure you could make something like a Jekyll plugin to handle specifying the origin of the blockquote and kicking off finding the h-card and doing the style pull for that within a static build.