Cut his hair whilst drunk.
or
Tell all his mates that he's still sucks his thumb whilst cuddled up to his favourite teddy
or
Sell his favourite possesions to pay for his theft, and then make him do press-ups till he pukes
or
Go to your local copshop, ask them to come round and put the fear of god into him, then tell him you've called them
or
Call the rozzers
Seriously though, I would go down either the Police route (asking them to come and scare him, not actually reporting them) or a severe punishment.
Another idea is to remove everything he owns worth more than £5 and lock it away. Make him sleep under wool blankets and wear clothes from a charity shop.
I phoned my brother the other day and he had just put his two on the naughty step for bickering - after the time-out their punishment was to listen to him playing a tune on his guitar. They are aged 6 and 4.
Grounded until he works to pay you back. If he refuses...no privileges, pocket money, treats, no birthday or Christmas. To be honest I'd withdraw privleges anyway for a while until it's all paid back. You need to be tough on this one otherwise he will never learn.
I'd ground him for about 25 years and withdraw pocket money plus make him work on household chores until he has paid his debt off.
Ummm, if you want to email me on FB, I can give you chapter and verse on "theft" or "obtaining a pecuniary advantage by deception" and what the sentences are if you want to really read him the riot act.