Trophy Hunting is a blast!!! I also got to help Hunt down some Trophies for our State Shoot. There are as many different things to get for Trophies as there are Shooters. I talked to the shooters and got some real unique ides from them and then went on a search.
Most newer shooters want leather, more experienced shooters don't because they already have enough. Knives, Guns, Money seem to be the most mentioned in My queries.
I was only in the market for one days worth of trophies (49) With that being said, check a few places because it will be difficult to get 450 trophies from one supplier if You want to have enough different items to satisfy everyone.
I can recomend Milt at Leach Laser in Phoenix he went out of his way to show Me different things that would be worth Winning at a State Shoot They have alot of options to choose from and does VERY nice Custom Engraving and Design at a reasonable cost with Excellent Customer Service. Milt is a Trap Shooter and an A.T.A. and A.S.T.A. Member, I felt it important to support Fellow Shooters, and Made in America products while working on these types of projects. I can send You his contact info if You are interested.
I'm with Longshot and grnberetcj. Go with gift cards to suppliers that support your shoot, or with free shells. Winners names will be posted in Trap & Field, thats the trophy, but the prize should be something useful. JMO.