Try Superior Building Supplies (.com) for great faux wood products.

I imagine what you mean is that you need something non-combustible in lieu of wood, so be careful about faux wood, most of which is a foam composite and is actually more combustible than natural wood.
If you can use cast or natural stone corbels, that might solve your problem: http://www.bracketsandbeams.com/products/Rustic-Precast-Faux-Stone-Corbel%3A-5%22h-x-7%22d-x-3%22w.html#

Try Durabrac. It's what they do. www.durabrac.com

Try Durabrac. It's what they do. www.durabrac.com