As others have said, this is not "cute", or "darling". This is not "sneaky as heck". He's not Mike Teavee from a fictional movie.
What he is, is a controlling rebellious child-in-charge who has no consistency, no limits, and immediate parental attention (negative or positive) for disobedience. He knows how to bargain and he knows that anything put in place to actually parent him effectively will only last for a couple of days.
You are on such a dangerous path.
I think some extreme measures need to be implemented. Tonight. Not high-tech alarms. There are some families with children who are affected by serious medical diseases (like Prader-Willi syndrome) who must resort to locks and alarms because the children are intellectually or genetically incapable of self-control. This is not the case with your son. He's extremely capable.
You must be stronger. His room should be stripped of everything except a mattress, pillow and a blanket if the weather warrants it. No Legos of any kind. No toys. No TV anywhere. No outings. Rent a storage system and put all the electronics and Legos and toys in it for a couple of months. Stop referring to a number of days in which he must obey. Take away the alarms. Sell the PS3. You are showing him that you're not capable of parenting him and must rely on electronic systems to control his behavior. He's learned that all behavior is tied to electronics.
Ask for a sleep evaluation at a pediatric sleep study. As well as a physical test, a qualified therapist will help evaluate the behavioral part of sleep.
Before you teach him self-control, you need to teach him that YOU, the parents, are in charge. A child first learns to obey. A toddler learns that, when in the grocery store parking lot, he WILL hold mommy's hand regardless if he wants to or not. Then, when that lesson is thoroughly learned, and when the child is older, he has developed enough self-control so that he can walk beside mommy independently, without any fear of his darting away into the path of a car that's backing up. We never teach a little toddler to first learn self-control in the parking lot. They aren't capable. We hold their hands as they squirm and wiggle and protest. But we know what's best. After awhile, they demonstrate self-control, and they get a reward (not a toy, but the reward of independence). They can walk by themselves. They can push a little toy cart. They can hold the box of Cheerios like a big boy.
Yes, it will be hard. It's hard when we are seated at a restaurant and are about to taste that delicious warm bread and our child pitches a major fit and we have to leave the restaurant and eat leftovers at home. It sucks when we have to leave the grocery store without the groceries and take the screaming tantrum to the car. It hurts when we have to cancel plans with friends and sit at home because our child couldn't stop acting out of control at the park. But it shows the child who is in charge, who is responsible.
If you can't teach him at 7 not to paint the toilet with your makeup and not to get up to watch tv and not to steal keys and manipulate alarms, what will you do in a few short years when he can get his learner's permit?
And all the adults need to be on the same page. No post-it notes. Have a professional evaluate him and write a plan which all the adults must follow (teachers, parents, etc).