The next question is do you want it now or in 2008/09?
There is a severe lack of mod shop availability, so even if you get a passenger Boeing, it will take over a year to modify it.
The only VIP A340 that was available has just become HZ-HMS.
The 767 VP-CME is back on the market but it would need additional tanks installed to satisfy your requirement.
The Oger 777 is still advertised on the net for sale.
Enjoy yourself
Mutt