carbon fiber and/or aluminum shops?

[MetalMan]

Carbon Fiber is pretty inexpensive here:
http://graphiteelegance.com/catalog/index.php?cPath=1
I would buy it there if I ever needed it.

Go here:
http://www.industrialmetalsales.com/Aluminum_Plate.html
And send these guys an inquiry asking how much the aluminum would cost. They carry 6061 and 7075. I just sent an inquiry to them earlier today asking about the cost for a sheet 1/8" x 12" x 24" in 6061, and I am waiting to see what their price is.

Normally, I would buy from Speedy Metals on Ebay for 6061-T6 aluminum. It is very cheap there, but they don't seem to have any single 1/8" x 12" x 24" sheets. Look here:
http://stores.ebay.com/SPEEDY-METALS...QQftidZ2QQtZkm

[BrianG]

Thanks everyone, I'll check out your suggestions. Now that BL Revo version 1 is complete, I'm starting on another design and was looking at a way to put the battery trays under the chassis to lower the CG and give me lots of room to lay out various parts. I want to make this one as light as possible, yet structurally strong. Since the batteries will be under the chassis, the bottom plate will probably be subjected to dings and scrapes. Nowing this, which would be a better choice for the under carriage - Al or CF? I would say Al, but CF is lighter...