Make them yourself...
You can get crimp on terminals to make the correct lengths, or even better are the screw on/ crimp fittings. The screw type has a nut that goes on the cable then you put the stripped end into the fitting and screw them together. I covered the connections with shrink tubing. They looked nice and worked even better. NAPA had the fitiings in the large sizes, but I had to look at the catalog myself after the parts guy said they had nothing like what I wanted, well 10 min later I found tons of fittings, and parts to make just about any type cable I could want. Marine supply places may have some also, I was in Annapolis last weekend and I think I saw some in the supply shop there.
I made mine from 0/1 gauge, even thincker than the 0 gauge. They weighed a ton though.
Have Fun