If someone can
write code for this, English Wikipedia would dive upon
it with great glee.
As far as I understand the proposal, it's perfectly possible to
implement immediately with no code changes. Just create a page, say
Wikipedia:Refs, and make a subpage for each reference you want.
Later, if it catches on, you can convert it to a proper namespace.
Well, I'd make them subpages of Template:Refs, to make the code
shorter, but otherwise, it's not a bad idea.