There is an ASCE 7 - 10 spreadsheet available on the steeltools.org website ( sponsored by AISC ) by David Taylor. Is what you are analyzing a sign or a fence or is it a very thin building? I don't know if his spreadsheet specifically address your problem but it might provide help with the solution. There is always the ASCE 7/10 Minimum Design Loads Manual available from the ASCE. Are you looking for Main Wind Force Resisting System help or Components and Cladding assistance.