I've got 1000 feet (literally) of 1/0 welding cable left over from a commercial shoot. We don't need it anymore and I'd love to pass it on to some EVers who are looking for a deal.
We hacked it up a bunch into many different lengths and crimped on lugs. But we didn't use heat shrink, since it was just a short term project. That will have to be added later.
The shoot was in a dry lake bed, so the jackets are covered in dust. It comes right off with water, so I'm not too worried. But you'll have to clean it yourself.
Let me know how much you need, and I'll cut it off for you. I think $1.50/ft is reasonable. Let me know if you want smaller pieces with more lugs already crimped on, or longer "pristine" pieces. I'll charge you the actual shipping prices. All of this copper isn't light. I'm in LA, so if you want to come pick it up, we can easily arrange that.
By the way, the commercial is here
And good luck with your conversion!