I asked the same a few months back, didnt get a great response

But i understand where you are coming from, you can do as much as you can a week, the make another few hundred quid on top by renting, subbing, selling work... This will keep you under vat but earn you a nice few quid

If you have alot of comercial work however i would not be scared of the vat threshold, and some have even managed to go over vat in domestic too so if you are building your business so big i dont see why to be afraid of vat?? Certainly if you can get enough work and clean enough to earn that much - you will be well capable of handling a business over the limit
There are of course many "dodgy ways" of keeping below the limit, but i wouldn t recommend them as its too much of a risk!!