Hi John,
As far as delivery to USA is concerned, I would suggest that an international carrier such as Fedex or TNT is contacted. They are normally able to pick up packages from the sender's location, but the problem my be provision of safe, sturdy packaging - such as a flight case - for such a long journey. With regard to the KN7000 in question, the seller states that he would prefer the buyer to actually pick up the instrument, which would indicate that he may not be willing to provide such packaging.
As far as the differing AC supply voltages are concerned, there are two possible solutions :
1. Use an external Auto Transformer to step up the US 110/120 volts to 230/240 volts. Such a device should be available in outlets such as Radio Shack.
For example:
http://www.radioshack.com/product/index.jsp?productId=2104179 2. Have a suitably qualified service technician replace the internal Mains Transformer with one suitable for 110/120 volts.
Quite honestly John, considering the problems and cost involved in transportation from UK to US, I think it would be a better proposition to try to source one in the US or Canada. Have you tried our friend Walt Tenay?