Hmmm....the only one I can think of (cause its the only one I've played) is Super Mario World 64 DS. I know they were pretty mean to him in it. Some of the bosses if you go and rebattle with Luigi dont recognize him at first. Toad is always saying negative things to you as Luigi. Then he changes his attitude toawards the last boss.I forgot witch Mario RPG it was, but the one for DS I think where everybody in the game had no idea who Luigi even was due to him being in a lack of games.
I'll get some quotes later from it. I dont have my DS with me
Speaking of which, I only play as Luigi in that game