The GTS online trading system only lets you see six trade offers at a time, and every search I've tried has given me six trolls claiming to want impossible things. Mainly sub-level-10 legendaries.
I guess if I wanted to waste some time, I could hack in a few boxes of level-1 Zekroms and clear out the ones in the categories in which I actually want stuff. But I don't actually want to waste some time on that particular thing.
So I just hacked in the Pokemon I actually wanted instead? Sorry, real Pokemon trainers, I needed that Umbreon! Umbreon is important to me.