The concept of a multiuse support ship has been around for over a decade, and the Dutch Zuiderkruis has been functioning as such a support ship since the 1980. With increased interest in peacekeeping operations, more nations want some JSS capability.
Canada, too, is interested in such a ship but cancelled an earlier attempt as costs rose.
It seems to be that there is another way to go rather than building a dedicated JSS. Why not use the modularized auxiliary cruiser concept I outlined here in order to build components that can be put together as needed on a container ship? It won't have all the capabilities of a dedicated ship, but it could be built--unlike the Canadian ships that were too expensive to build.
UPDATE: The Dutch might need such a vessel to command a relief expedition to recapture any of their Western Hemisphere islands in range of the Nutball Hugo Chavez, who is planning to double the size of his Marine Corps' amphibious force:
The two new marine brigades will take a few years to get trained up to a standard close to that of the existing two brigades. It's possible that the entire Marine Corps may become less effective, as president Hugo Chavez has been forcing the military to undergo a series of reforms that place less emphasis on traditional training and readiness, and more on political correctness and loyalty to Chavez.
On the bright side, if the Marines have any residual combat capability, diluting it with Hugo's strategic thinking could make them a farce to be reckoned with.