The hobby is pretty bad with names. Too many same terms applied to different things, also the same thing given different names. "Calico silkie" is one of those examples.
It has been used for a Grey with red on it. I have seen birchen patterned ones called Calico.... The one above is a new one to me, using mottle.
As for the OP, I actually saw that same example called calico just last week.. it WAS a Splash with red leakage. The same thing as a black with 'unacceptable' red on neck and back except in Splashed version. I will say it did look 'cool'. If this is the version you are looking for then your idea was on the right track, crossing a blue or splash with a partridge is a good way to get 'leaky blues'. Or you can look for a black or blue line known to be very leaky, with lots of red areas. If you get lucky and find a blue leaking red, you can breed them together to get the splashed leaking reds for that version of "Calico". If you find blacks leaking reds, just breed it with a blue or splash to bring in the blue gene and then breed back to the leaky blacks/breed two blue leakys together.