Speed knots    Range, endurance
                     Max/cruise/loiter

Atlantique 2            360             6700 km/18 h/1850 km+5 h/960 km+8 h
   See also http://www.dassault-aviation.fr/products/atlantic.htm
Atlantic 1              355/300/169     9000 km/18 h
Orion                   411             8950 km/17 h/2500 km+3 h
Nimrod                  500/425/200     12 h
Hercules                325/250         5780 km @payload 14 tons, fuel 36 tons
Fokker Enforcer         280             5000 km/12 h
CN-235 Patrollero       252             1950 km/10.5 h
Tu-142M                 510             8250 km

As comparision, a few civilian aircraft. As you see, the large
ones use a lot of fuel to get their long range, so it can't be
increased much by sacrificing more payload, and I'm not convinced
they can achieve these ranges in the operational environment
of a maritime patrol aircraft.

Boeing 747 SP               375        16459 km @payload 12 tons, fuel 190 tons
Airbus A340                 330        16200 km @payload 22 tons, fuel 147 tons
Airbus A319                 360         7800 km @payload 5 tons, fuel 23 tons
BAe 146-200                 300         3560 km @payload 9 tons, fuel 13 tons

Most of the text updated 1995 Feb 03.
Some data added and corrected 1997 July 23.