Wikipedia seems to be the closest thing we have to broad distillation right now.

It works pretty well if you are researching a subject in depth. The technical articles tend to be written by experts for experts and they have lots of links to primary sources.

But, as you hint at, they are poor quality because they are being written by a committee.

I would love to see a collection of community written distillation articles, as you describe. Perhaps with some kind of taxonomy like Wikipedia's.