Defiant 11 year old- not sure I can take it anymore!

We have an 11 year old fs.I could write a book about his behavior problems, but that would take too long.Long story short, he is absolutely driving me nuts with his defiance, throwing things, kicking things, stealing my jewelry and giving it away to kids, mouthing off and peeing on our clothes (yes- he literally pees on my clothes and shoves them in the hamper). He's in therapy and we've discussed it all with the therapist. None of this is new, we've gone over all of it before and it comes and goes. Lately though, maybe because school is starting, he is driving me nuts! I am out of privileges to take from him. I'm not exaggerating either... we have sold his Game Boy, taken away TV, computer, video game and radio privileges, taken away his bike privileges, etc. This is over the course of a few months. I am completely out of "punishments". We try to prevent the behavior in the first place, but we're not having much luck. So my question to all of you is "What do we do next?". I've actually resorted to having him stand in the corner on 2 occasions lately, something I usually disagree with when other parents do it, and even though I'm aware it's not helping him learn a lesson, I just don't know what to do any more. I'm trying not to lose my patience, but quite honestly I'm 5 months pregnant and grouchy, and just not in the mood for the defiant attitude anymore. Any ideas?