Did you look at the STS Turbo website? The market a turbo / Dual turbo bolt on system that are for multiple applications, and their turbos are taking in air from the rear of the car, usually around the gas tank or in the spaces between the bumper / rear quarter panel and the body sheet metal / frame.
http://www.ststurbo.com/parts___accessories1
Poke around the STS Turbo web site and look at the mounting locations for various applications. Might give you some ideas, also they sell shielded air cleaners and air cleaner relocation kits.
Did you check out the Specter website? They have kits that are application specific that might work. Below is the link to the 1970 to 1981 Camaro air cleaner kit. It doesn't route the filter through the radiator core support, however it puts the air cleaner in the corner between the fender and the core support where it is getting cleaner / cooler air.
http://www.spectreperformance.com/#CATALOG.900121
They also sell pre-bent tubes and flanges that can be modified for universal fit applications.