Set up 4 websites on a single magento installation.
1 to 3 would operate as individual web sites with seperate themes.
.[url removed, login to view] redirecting overseas visitors to .com based on IP address.
On .com we would configure to display prices without VAT and do a further check on shipping address.
All 3 would use PayPal pro as their gateway.
.net will be tied to visits from a specific fixed IP address from our shop. All other visitors will be redirected to .com / .[url removed, login to view]