If you google 'woven wire' there are loads. Here are a couple from the top:
http://www.wovenwire.co.uk/
http://www.wirecloth.uk.com/woven_wire_mesh.asp
This one sells brass/steel/copper mesh in A4 sheets:
http://www.themeshcompany.com/acatalog/woven-wire-mesh.html
Hope this helps.