I follow Izzy on FB, and he introduced this clamp rack system the other day. It lets you mount four clamps and when gluing up a panel the clamps are held upright and evenly spread across the width of the panel un to 5 feet apart.

It looks like you could make you own version if you wanted to take the time to do so. I don't know if I would buy them, just thought some of you might be interested.