As I was removing the cables this morning on my '47, which still has the battery under the floor, I was wondering where I was going to come up with a 4 ft. long cable on such short notice, as I'm sure they're not the most plentiful item in town. Then it hit me. We have a farm equipment dealer about 5 miles from where I live, so I stopped there. Turns out, they had the cable in bulk, along with all the different ends, and were able to custom make exactly what I needed. And it cost less than $20!
They also had the heavy gauge cable, so later on, if I need cables for my 6 volt stuff, I can get those there as well.
Just thought I'd pass this info along, in case anyone else had this problem.