Just thought I would share a place in North Texas that will cut aluminum sheet. This is a semi trailer repair shop
www.dallastrailer.com I emailed them today looking for wide aluminum however long you need it and they came through. It is mill finish, .050 thick, 103" wide and up 700' long if you need it. They use it for the roofs of the semi trailers. The phone number is (972) 579-9027 and talk to Tom Henson. I do not know if they will ship. But the price for the aluminum is a lot less than what I have found else where.