Only problem with your theory is that's NOT what VT is for. It's Vintage Tech, do we need to look up the meanings of those two words? It's not called "Unreleased & Unheard Tech" so it wouldn't be wrong to put older songs form Calm and such on there. Though, I hope to not see something like they did with the last one where half the songs from the bonus disc with AP was on there, since those aren't exactly "Vintage."
Though, don't get me wrong, I'd also love to see some "Unheard & Unreleased" ish too.
EDIT: I think SmittyCal put it a little better, Lol.