EVGA. Most shops have them. They come in a few different sizes. Yep, could put another card between or move my bottom card up two slots, and the bridge would work still, too. They make a 1x-wide bridge in two sizes (for cards next to each other, or one slot apart), the double-wide triple, which works for both dual and tri configs, and the quad bridge which is obviously double-wide as well. No matter which bridge you need, they are all $30 each.