There are a great many aircraft capable of delivering the range - the difference with nimrod was endurance/dwell time.
Who knows, by the time this could be sorted the EU boundaries may be in use and the need to go to W30 may no longer be 'required' for the UK - perhaps that could be France's interest?
Equiping aircraft with the role equipment is key to the job. There are a plethora of aircraft already designed and approved for a wide variety of roles in civil and military guises. All could be operated by a civlian organisation.
The need for multi-roled aircraft is another consideration. It may not be cost effective to put all roles into one frame especially if some roles are not regularly used. This would possibly avoid the gold-plating approach and allow specialist stuff to be held back (or the percieved need scrapped).
What I'm trying to say is that there are many ways of skinning this particular cat. You may or may not be aware of some of the alternatives, but they don't all need to be nimrod or military operated.