Hi Andy
I did give some thought's re fuel tanks
A couple of the major drawback's for me, one would be the very high cost of alloy sheet in this neck of the wood's, the last sheet of 1.2mm cost me £47 & I dread to think how much the 2mm is per sheet now
but by far the biggest drawback is the lack of a suitable sheet metal bender
My own tank was made out of sepperate pieces, this meant 3 extra seams to weld & greatly increases the fabrication time, not to mention the extra Argon consumption.
Been scouring ebay for a decent locost box folder for years .... Allways fetch silly money or are a gazillion miles away