Mnemosia

Hello, I didn't know where to put this question, so I thought this was the better place. Can I exchange art for bonuses? I'm a fantasy artist and I thought I could offer my art for some bonuses for those interested. I can offer wow character portraits or full-bodies for example. Or even another type of art, at the taste of the customer (: But first I would like to know if that's not forbidden ;D Also, how are bonuses gifted to other user? I can't find the option at the web :S