My initial reaction is: I should probably get around to learning about Flakes. I’m not sure I’d want each blog post to pin its templates, but it’s nice to have that choice.
Personally, I think I'd use two flakes, one that builds the content into something that's ready to hand-off to code, and a second one that turns it into a usable site. That way you wouldn't end up with a new input for each post, but instead would have a versioned something which represents your content all bundled together, and then the site builder consumes it as a single dependency--but conceptually it's the same.
I guess I'm just saying that it's not conventional, but it's a pretty logical conclusion to reach.