What does the UK government say they want to negotiate state-by-state? I doubt it would be constitutional to any meaningful extent though:

Quote Originally Posted by USC, Art. I, Sec. 8
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;

To borrow Money on the credit of the United States;

To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes
I believe a foreign company can come and negotiate various arrangements with states or localities, such as tax abatements and other incentives, but if it's a government entity, not even that much may be permitted.

Seems like a subject for the blogs and Twitter experts.