heres the 50 cal cans if you were skilled enough you could make a compartment in the can to hold fuel then leave half of the can for tools or whatever else youd like .
this would work realy well cause you could lock the can up secureing your fuel and tools.
sorry the cans are so dusty bike was ageing .
if you were to do the ammo can saddle bag id recomend that you look at 7.62 cans to their about half as wide and may give you that more stream line look .
google fat 50.cal
these are ammo cans that open from the side and are sliigtly wider