Here's the thing though. The US price, direct from Apple, via a freight company (bundlebox etc) isn't going to go up. The UK price is unknown. So if the UK price comes out at a load more, then you can make the choice to buy from US and not UK. However, it's a win win situation as the UK version might come in nearly as cheap as the US price+postage+VAT but you get to support UK economy and get it in person etc.
Are you seriously suggesting Apple would lower their profit so that AFTER vat the prices are more similar? That's the most bogus thing i've ever heard. They're so profit conscious they won't even spend $5 per machine to add 512mb ram to maximise margins. Expect iPads in the UK to cost £££