I doubt it would be that big of issue. Theres other virtual worlds or chat sites that allow the change of your username, which do not hold this issue you claim, the amount of money Second Life makes would be able to conpensate a software update or change to allow this option.
And before you make the comment "then use those virtual worlds" or something in that nature, I do use those worlds, I like Second Life as well, so I'm not going to leave it, I'm just suggesting an idea/ability.