My wife and I were in Babys R' Us yesterday, and I found a couple things I found to be interesting... Mirrors designed for keeping an eye on your baby in the back seat. The neat thing, they are adjustable, and are made for sticking to your windows! Exactly what I was looking for earlier this year...
This model is a round convex mirror with a suction cup. It looks like it would do a pretty good job. I didn't measure it's size, but it seemed kind of small for doing the job of replacing an external mirror. PRICE: $3.99USD
This model actually came with TWO LANDSCAPE MIRRORS (so you don't get the sun reflected into your eyes like my current drivers side supplement), and each of the mirrors has TWO mounting options, a suction cup OR a visor clip! PRICE: $4.99USD
I got the dual landsmape mirrors. They are convex, but more landscape, like if you took the top and bottom off a circular convex mirror. They are about 3 3/4 inches wide, and should do a good job at filling in my blind spots. I will update with new pictures once I get them "installed"...