We have the same issues here, too. ONCE they know you have a tank, the database has your name in it....location, size and age of the tank,,,,,BLAH, BLAH, BLAH. also, the delivery company has to do the appropriate paperwork, also.
EVEN being 100% legal makes it a tough decision, and the cost may exceed the price at the pump. I no longer have anything underground, and approved 'mote tanks' aren't cheap.
I sure understand your dilemma, and don't think you can sneak anything by the Locals...they have satellite files that will blow you away. As you know you can have portable tankage not to exceed 100 gallons in most states.
You just might have a couple 330's for 'home heating fuel' and everyone knows you can use #2 in an oil fired burner. I know you will find a workable solution.......