hmm... Trophy specials... nice idea. Although I don't think they should have a specific look I think it would be much cooler to have them as things to do with the level maybe like a statue in one level and a pool in another (something would be mentioned at the start of the level about it or something and when you hover your hand over it it would say the name of it). When you claim it you get the benefit from it and this can change sides. Maybe they could be in a treasury or a special room so that when you claim the room you claim the trophy.
It would probably be foolish to have treat tis te same way as a specail because it's not. If you have it in your treasure room you could just pwn because the enemy can't get it until they've almost killed you giving you a massive advantage until that time. It should really be treated like a manor vault as it is actually quite similair in function.