Is it conceivable that you design your second identity, your SL avatar, as everything you would want to be, but can't? I think it is, and I see no problem with that. Phantasy is free. You don't even need SL to create a phantasy world. This tool allows you to have it and share it.
It could even help you soothe your schizophrenia.
I understand there is a code of ethics in this medium. Violence and ruthlesness are not allowed. Offensive behavior in general is not tolerated.
Am I becoming an old conservative-minded moron? I hope not.
I must admit I haven't used SL yet. I will post something else once I've worked with it a little.