Here's the one I built. Mine's bolted together, though, so that it can be taken apart for removal if necessary.
http://rides.webshots.com/photo/2795752150092261295jsYBND
http://rides.webshots.com/photo/2513502400092261295puxAHX
It's mounted to the floor with 1/4-20 bolts.
This pic shows how it's clearanced for the filler tube.
http://rides.webshots.com/photo/2924688900092261295VnrwkW


Bill Burmeister