hay guys im working on a project for a friend and he wants to know what is out there as a industrial AP

also if there are any AP's that will work as a mesh network. because that would be a bonus for him.

range wise 500 feet with an omni antenna would be a good distance but further would be better

and a $300 budget but up to $500

Wrong country, however may give you an idea of whats available.
http://www.solwise.co.uk/wireless-wap-854gp.htm