Broadband Design
Without the tremendous work of Steve Hunt G3TKQ we all would not have this broadband hexagonal antenna.  His web pages contain the detailed theory of both the Classic and his Broadband design.
http://karinya.net/g3txq/hexbeam/

Mast Options
This is a popular push-up mast.
http://www.3starinc.com/rohn_h30_telescopic_antenna_mast.html

Parts
Fiberglass spreaders and many other amateur related parts.
http://www.mgs4u.com/index.html

Do it yourself
Interested in home brewing your own antenna then Leo Shoemaker site has it all.
http://leoshoemaker.com/hexbeambyk4kio/general.html