I do remember at least one RPG where all weapons had a length between 1 and I think 6, and the guy with the longer weapon had a pretty massive advantage, unless the guy with the shorter weapon managed a tactical "closing in" action, and then the other guy had a disadvantage if his weapon was too long. Sounds like something like that could easily be implemented in a computer game and built upon.
Edit: half-swording and pommel strikes etc. were also in there, with some weapons you could lower the damage slightly, but make them shorter, to negate disadvantages in a close grapple.