Davenc,
Radium Engineering makes the best stuff that I've seen. Here's their link.

http://www.radiumauto.com/FST-Fuel-Surge-Tank-Standard-P515.aspx

There are basically 2 fuel circuits in my surge tank system. The very low pressure circuit from the tank, to the surge tank and back to the tank. This circuit free flows at nearly 0 psi. It supplies a mostly uninterrupted flow of fuel to keep the surge tank full. If the tank pick-up does get uncovered during low fuel level operation, the resultant bubble in the line is quickly purged out of the surge tank and back to the main fuel tank.

This allows you to run an inexpensive stock tank by simply increasing the size of the return bung to match the output bung size.

The second circuit in my EFI application flows from the high pressure fuel pump submerged in the surge tank through the fuel rails and then the adjustable pressure regulator on top of the surge tank and back into to the surge tank. The high pressure fuel circuit is short and does not run the length of the car.