Ridiculous. First, the antifederalists (the real federalists) had a document--The Articles of Confederation.
Second, the delegates in Philly were sent to the convention to fix the Articles by adding a few specific powers--they weren't supposed to create a new system. In other words, the antifeds had already offered their ideas and sent delegates to act on those ideas.
Third, The antifeds didn't create a constitution because they were against consolidating the government. They believed in a union of states--not a single, unified, consolidated, supreme government.
Finally, they didn't hold a convention after ratification because they had lost the political battle. Most antifeds followed Patrick Henry's example. Once the Constitution was ratified, they accepted it and moved on.
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.