I don't think that appealing on the Steam forums will be worth it, since you need to contact Valve directly via a support ticket. Also, I wouldn't ever try buying or selling a Steam account, since that is also against their terms of service. If they find out about that, they will disable your account.

Since Valve probably hear a million "I didn't know it was an aimbot" excuses a day from people who fibbing to get themselves unbanned, I think it would be extremely unlikely that you would get any mercy. Good luck though.