Ronco Plastics (no relation to the VegoMatic Ronco)
Ronco Plastics makes TOP quality thick walled rotomolded (at least 50% thicker than most OEM
tanks and ANY off-the-shelf tank) plastic
tanks for a very reasonable
price and has more than 400 shapes and sizes, over 100 of which are non-rectangular. And they install fittings in the sizes and locations specified by the customer when they make the tank. If you can't find a good fit among all those, Triple M Plastics is prob'ly your best source for a one off custom tank.
Triple M Plastic Products Inc The only downside to Triple M is, their prices are VERY reasonable
for custom one-off tanks, but that's still gonna be 2-3x the price of a rotomolded tank for which the
mold already exists. And, they're in ME, which can make
shipping expensive
You do not need a macerator to empty the tank...a manual
diaphragm pump will
work just fine.