If you find a tank that fits then it shouldn't be too hard to install an in tank pump and filter. Make sure the pump and filter will be deep enough in the tank to grab gas at the bottom, you don't wanna install a 30 gal tank just to find that your pump starts sucking air in after 15 gallons. Just enlarge the access hole to whatever size you need and bolt it in place. When enlarging the whole make sure you don't get metal flakes in the tank. I saw one of the power block guys putting petrolium jelly on his drill bit to hold the flakes in place so they don't fall in the tank, or at least not so many flakes will fall in the tank and cleanup will be easier.
