I like that idea, that's what I would do. That EK kit, with an EK GPU block....and then a nice D5 as an extra would probably work very well for you.
But then some might say, just piece together the whole kit yourself anyway. When I had my original kit, it didn't really take long, little by little I start changing things out....first the fittings and tubing, then fans, then the reservoir....eventually I realized I should have just pieced together my own kit from the beginning.
Just something to consider.