Dave,
This a post I made awhile back check it out. I have built this bender and, it works real nice. The brake rotor idea will work but it is alittle more work. Hope this helps you out. Good luck getting job. Keep us posted on your progress.
Here's the link that was in the other post that I forgot to link you to!!! DUH!!
http://www.bbssystem.com//files/smau...bender_102.pdf
It really makes a nice little bender.
Larry