That 90 minute DVD could be interesting, but I'm going to guess most of the matches will be clipped and being the TNA mark that I am, I've probably already seen what's on them.
Considering there have been 2 Elevation X matches (Rhino v. Styles, Rhino v. Storm) and 1 Terrordome match (the one from May), I imagine you'd be correct. There's only a few possible Ultimate X matches (6 for the X Title (including the Ultimate X Challenge match years ago which didn't work), 1 for the tag titles, the one from Best Damn Sports Show, and the several for the World X Cup we're looking at around 10 or so) and even less King of the Mountain matches (5).
Given the mention, I'm expecting the World X Cup finale, May's TerrorDome, March's Elevation X (Rhino v. Storm), and the June KOTM as the "90 minute" DVD. Given the length of the matches, that would make about 90.