Ant -
The electrical switch (or read below) is really the better way to go if you can tie both tanks together. But the cool factor of the manual switch goes a long way as a gadget-teer. The other thing is for non 24hr or endurance events you likely are going to be fine on one tank
MR - Could be done, If you have regulators that need to bypass fuel back to the tank then you can't easily do the check valves since the fuel from one tank must recirculate to the same tank. If not, the check valves would work fine. For EFI and 2 tanks gets tricky, carb an no bypass back to the tank, easy. I think we beat that horse dead in another old thread which was was a good thread about fuel systems and all the valves, bypasses, specialty efi valves, and of course the swirl tank etc.
Sandy