Great question of the fuel tank:
First, here is some information on my installation:
http://www.expeditionswest.com/equipment/tacoma/fuel_tank.html
I spent a few months researching the options, and these are the results.
1. The only commercially available solution is from Downey, a 15 gallon unit. It is over $800 with shipping
2. In-bed options (like the tool box units) are nice, and an easy install. But I wanted the weight lower and could not afford to loose the bed space.
3. The race cells are not a good choice, as skid plates are a challenge to make and the fills are typically on the top. It also requires an in-line fuel pump.
4. OEM solutions are the best, and least expensive option IMO.
A. The Trooper tank allows lots of capacity (22.5 gallons), but you will loose ground clearance. I dont really care about the 4" I lost, as the lift and tires brought that back. It also has a HD skid plate and a fantastic in-tank pump.
B. The Suzuki Sidekick tank is small (15 gallons) and allows better clearance. It also has an in-tank pump and skid plate.
BajaTaco built a nice, high clearance tank (14 gallons) for his truck.