Revel wrote:
I've seen many times a Samurai going apeshit and wielding a katana with 1 hand, and his seppuku blade with the other...
It's called a wakizashi, and it was used more as a back-up than as a seppuku sword. And as for the wielding both point, yes, they did. Musashi Miyamoto, for example, had a tendency to use both his katana and his wakizashi when he was fighting multiple opponents, but that's not saying much, since Miyamoto, despite being one of those "legendary swordsmen" just used whatever was most convenient at the time.
As far as this topic goes, though, yes, it'd be nice if one could switch wielding a katana in one, or two hands, but since we can't do that with bastard swords, I don't see much of a point. Making them two-handed would be kinda dumb, though.