If Anti-federalists are actually going to try to resurrect the Articles of Confederation - adjudged by everyone as a failure after only 6 years over 220 years ago - hey, good luck with that. If Anti-federalists aren't going to try to resurrect the Articles of Confederation, they'll actually have to come up with a document, or or they can just be irrelevant. Their call. No tickee, no shirtee.
I think it's pretty obvious that antifederalism (actual federalism) has been politically irrelevant, as you point out, for a very long time.
It's not a question of coming up with "a document." The Constitution forever changed the FORM of government. It went from a simple Congress of states to a consolidated nation/empire. There's no putting the toothpaste back in the tube on that one.
The relevance of it all, to me, is to better understand the current situation. Antifederalist writings help me understand it all much better. It helps me understand that the Constitution is the source of the problems.
Answer: Confederacies do not constitute government.