Jim Carter also has a 1 ton e-brake cable set.
http://www.oldchevytrucks.biz/catalog1/0083.html Even though
American Classic sponsors the site -- and I do always check there first -- I've found that they don't have much for the "bigger truck" crowd. Jim Carter, OTOH has had everything I've ever needed -- and then some.
If you're hell-bent on fabricating your own -- and let's face it, who amongst us hasn't thought about it -- I wouldn't use bailing wire to do it. I'd go down to a farm/industrial supply outfit and get some steel cable. Baling wire may "bail" on you when you need it the most... And that wouldn't be fun.
At all.