cobaltblue is right on the mark. $40k gets you a new fully outfitted 7-7.2m boat. The higher end boats european boats are about $20-30 k more. You will also pay a premium for the twins but for most offshore work it is certainly recommended. Make sure you get separate fuel tanks, filters, separators, etc... when you get your twins.
Since, very few RIB's of that size are manufactured in North America I would find it hard to believe that you can't get a better deal down there.
The best bargain boat at 7m is the Zodiac/Bombard Explorer 720. Make sure you order it with the internal fuel tank and anchor locker. This boat is of lighter construction and not recommended for extreme commercial work but for diving it is great. Plenty of folks have them and love them.
Good luck