Mm. I know at one point I was considering a simpler 2 v 2 format for a tourney but there's some logistical issues that would need hammered out. Though some are fairly simple at least.
The basic restriction I had in mind was each team needed to be from the same game. Beyond that, there's the open question of how many 'divisions' to use, and how to format the teams. For example, supposing we had two divisions, you might have one be a Heavy and a Middle/Light, then another be a Middle and a Light. But due to the wonders of synergy some characters might disproportionately gain strength in such a format, so perhaps it's better to suggest a target power level (say, mid-rank Godlike and mid-low Heavy)? Or just cast caution aside, have an Upper and Lower division, and restrictions like "One character may be a Heavy, the other must be Middle or lower" for the Upper, and a similar wording for the Lower? I dunno.