[rsync]

"Is there anyway to effectively "AMP" a page without maintaining a separate set of HTML/CSS/JS?"

Yes, certainly - it is well documented here:

http://motherfuckingwebsite.com/

and here:

http://bettermotherfuckingwebsite.com/

FWIW, we followed these principles when we created Oh By.[1]

[1] https://0x.co