FWIW, REI and Campmor both sell "featherweight" mirrors. These are thin, flexy plastic, like credit card stuff. They work fine as a normal mirror, and have a hole dead center for signalling. They really are lightweight- like 2 or 3 playing cards. Even if it won't do for your signalling needs, the extra weight of carrying one of these as well is pretty trivial.<br><br>