Sheathing a 5X8 TearDrop

I am definitely going to build a TD that is 5' wide. I have not decided on whether to build it 8' or 10' long. My wifes cousin has a sign company, so getting the aluminum, diamond plate, in the dimensions I need is not a problem. The problem I foresee is getting the 1/8" oak plywood that I want to line the inside with, in the dimension that I need so there are no seams.
I have had no luck at my local Lowe's in getting finished plywood in 5' X 8' or 5' X 10'.
Any suggestions from anyone that has build a 5' wide Tear?
Thanks,

I have had no luck at my local Lowe's in getting finished plywood in 5' X 8' or 5' X 10'.
Any suggestions from anyone that has build a 5' wide Tear?
Thanks,
