setup wheels

[38Buick 80C]

Has anyone seen the hard thin plastic wheels that can be used as setup, mock up or roll around wheels for your restoration. I saw a few cars at Charlotte Autofair were sitting on them but I can't find where to buy them. Basically the ones I saw are black plastic and have a varitey of different holes in them so that it can fit differnet bolt patterns I guess. I have looked on Coker tire's website and couldn't find them.

They'd be ideal for a car under restroation as they are only like 3/4" thick and hard plastic so they have very little rolling resistance.