I have a brand new survey vest size XL that I don't need. I already have this same vest! Lasts for many years. Sells new at Kuker Ranken for $119.95. I will sell for $80 firm!!! Has both zippered and open pocket in back (full back).
More info: http://www.krinc.net/25881/178656/Safety-Vest/Big-Sky----The-Best-Survey-Safety-Vest-in-the-World.html 
It does not appear to be OSHA compliant, or at least the ad makes no such claim.
website has a note: **Not ANSI rated.
Summary of Safety Vest Standards (with hard hats and safety glasses)
http://www.utilitysafeguard.com/customer-center/resources/safety-vest-specifications/
Browse through the SECO vests here to see what each class might look like.
http://www.surveying.com/products/pcat.asp?prodCatID=14
The ANSI standards are not a "pattern" for making a vest, just the requirements of what is needed for each classification. You'll see many styles of class II and III vests in the marketplace.
Wearing a green vest might be considered when working around orange colored equipment so a person stands out. Some DOT's seem to prefer the bright orange equipment.
I have no connection to either company.
Looks like it would be hot.