I had this very same problem on my car when I went EFI, it would surge below about 1/3rd tank. I came up with a pretty simple solution that works perfectly. Like other solutions above it allows you to use the full extent of the tank too.
Can be done with a few bucks worth of steel, MIG welder, cutoff disc/angle grinder, $4 generic fuel filter, and doesn't require a second fuel pump.
BTW for my high pressure pump I used one from a Ford Econoline van from late 80's, they are super common and about $70 if I remember. My setup makes 300+WHP and this pumps handles it fine.
In short I made a steel canister that hangs from the factory toyota drainplug. Graphic below of a cut-away should help explain.
Some notes: To keep the fuel in the canister from overheating (otherwise on warm days it will cavitate in the pump and make noise, doesn't affect engine though) split the return line between the tank and the canister. Make sure to completely thread the canister/drainplug weldment into the tank before positioning the nipples in the canister (preferably before welding on the bottom disc too, so you can debur the nipple welds.
2016-10-28: UPDATE - I have recently made some upgrades to this setup to make it more reliable. On a very hot days the fuel pump would cavitate/boil the fuel on the inlet size due to the restriction of the cheapo fuel filter. Car still runs, but the pump is very loud. Also, when I removed the tee - to return all the fuel to the tank in order to flow more of the cooler fuel out of the main tank into the canister (to help reduce the cavitation) - you would hear air bubbles escaping from the canister back into the tank after the car was turned off.
Fix: I replaced the fuel pump (same Airtex E2000), swapped the cheapo inlet fuel filter with a large Aeromotive 100 micron (PN 12316), and added an external, low pressure 20GPH 12V pump, to pull from the original in-tank pickup and pump into the side of the canister (returning to the main tank via the drilled out drainplug/canister mount). I haven't had a chance to drive in high temps 95F+, and prob won't until next summer, but seems like a good fix. We'll see.