Something that is being overlooked is the use of tiny cameras. I think the mirrors everyone has mentioned are great looking but marginal for functionality. I have been using small low grade cameras for several years now. I have recently upgraded to the small high quality cameras that are utilized in the RC industry(not those grainy little parking cameras). They have some really good quality cameras that are relatively cheap(under $60) and rival the quality of some of the bigger name cameras like the GoPro for instance(RunCam, Mobius, Sony and others). These cameras can be discretely mounted to give good viewing. You can easily access their settings and change any feature you want. They even have mirror functions that allow your camera to act like a true rear view mirror. Most run on batteries but can also be powered easily with some hardware that is very cheap($10-20). The monitors can be anything from the small(visor types) to Ipads(read expensive). You can get multiple cameras screens(4) that can also show one camera at a time, or 2 at a time, or all 4. Most are 7"screens(diagonal). Your only draw back to me is which optics you opt for. The ones with a smaller FOV(field of view) give a more realistic view of what is behind you. These tiny cameras(the size of a matchbox) can be mounted anywhere and can eliminate any and all blind spots. Some of these cameras can be mounted with Pan and Tilt mounts that you can manipulate to see in more than one direction by turning a small knob. they also can be used to record at the same time. The RC groups have done wonders with miniaturization and even have what they call board cameras with 1080P resolution( small computer chips(2"x2") with a lens mounted on it). Two of my older cameras(400 TVlines) are the size of a jawbreaker candy. Hid those in my side mirrors. If interested PM me and we can exchange phone #s and talk about it. Millions of Utube videos on the equipment, reviews, and how they work.
Bill
I even incorporated cameras mounted in the mirrors them selves