Does the fuel necessarily have to be returned?  What is the benefit of returning it?  Injectors can take 50lbs of pressure.  In fact, they make a better spray with the higher pressure, and atomize even better if the fuel is sprayed hot.  Many modern cars don't have a return.  As long as you keep the pumps  and the gas going to them cool, you won't get vapor lock. 

Keep the fuel pump below the injectors and behind the firewall.  It'll draw cool fuel and then pressurize it to keep it liquid until it is sprayed.  On shutdown, the fuel in the line firewall forward will get hot and vaporize, pushing liquid back to the pump.  But, as soon as the pump is flipped on the vapor gets compressed and liquified again for the rest of its time in the line.

I could be wrong. . .