I don't remember the venders name, but there was a vender at the ABF convention in January in Baton Rouge with a product based on the same concept. I remember finding it intriguing and thought it was a cool idea, but as with most IPM ideas, personally, it struck me as more trouble than it was worth.
I don't remember the exact design, I want to say it somehow attached to the front of the hive...I do remember it did have a little flap of some kind to partially obstruct the entrance to discourage them from flying straight into the hive and instead force them to land and "attempt" to walk in.
Good luck with it, keep us posted!
I did some digging around and found the company...
It's there entrance trap on there products page, although their website doesn't do a very good job of displaying it via pictures. However, their video page has a couple of videos on it.