To answer your question about DOM, there are no sources in the Provo area (I have never found it in Utah County). I've always purchased it at Marmon Keystone in SLC. Economy Steel in Spanish Fork may have some HREW. Years ago, I purchased some there but I'm not sure if they still stock any.
Post up a tech article to show the build of your new radius arms.
No problem.
I do live in Lehi now. I used to live in Spanish Fork though.
If you're going to Marmon Keystone, I'd suggest calling ahead. They may require it to be ordered under an existing or commercial account, even if you're paying in cash.
I need to round up a little DOM myself, I'm running out. :-\
Have you tried Metal Mart in Lehi? I used to buy HREW from them, but never got any DOM. Probably wouldn't hurt to call and ask. If they don't stock it, I'd check with the guys at Ben Hanks Racing in Sandy. They do a ton of fab work and could probably help you with materials.