I’m not sure I understand Brent Simmons’ problem, here.
If you need the same code running on two or three small specialized web-servers, just write it once in a library and include it in each of them. The repetition of running instances isn’t worth worrying about.
I’m wondering if his problem is really a lack of an obvious “include” for common html components in a world of single-page node.js apps? In which case, is this really a package management question?