Rue,
I am sure you have looked at this thread,
http://rctruckandconstruction.com/sh...?t=6241&page=4, Chris has put together a quote for aluminum track assemblies which look really good.
I am currently working on a steel alternative and will post as soon as I know the feasibility and economics for what you would be getting. I am doing this for my equipment projects and "if" it is economically feasible, I will go through the proper channels here to offer them to others. To see sample profiles go to the end of my thread,
http://www.rctruckandconstruction.co...ead.php?t=6016, and you will see what I have been working on in aluminum.