I too have heard a word used to describe the use of a brand name in this way. In fact, I heard it several years ago, and recall being pleased to have learned it. Maddeningly, I forgot it a bit after learning it, and its absence returns (if that can happen) to haunt me periodically.

So - can we come up with it here, or will this annoying lacuna in my vocabulary continue to be a little, tiny thorn in my side?