We're thinking about it. We were not going to allow members to start off with more than one character right away (in a way, members already start out with more than one 'character,' if you count the gamer and their avatar as separate entities—particularly if you play them as very different personalities). But we were also very seriously considering allowing members to to create a second/additional character(s) after their first character had reached a certain level.
We're not sure what level that might be yet. The reasoning behind allowing this based on level is that we would hope that, in reaching that level, said member has by that point displayed an obvious dedication to the group; hopefully, that would mean that they would continue to contribute meaningfully to the group, even while juggling more than one character.