Yet another mirror option. These certainly aren't one of the cheaper options, but they also don't require the extenders. I rode with them today and while they move a bit, everything is pretty darn clear. I wasn't sure what to expect, but there's no vibration. I can not only see there's something back there, but can tell what it is.
I don't have enough experience to know how they compare with much, but they're much better than the stock mirrors, both in terms of visibility as well as vibration.
They are adjustable both in terms of angle with the allen bolt you see in the first pic. Then they're adjustable length-wise. I have them all the way out.
The biggest downsides are that the 1) stem is simply metal and will rust, and 2) there is no lower boot. I'm not sure what I'll do about those two things. Henri suggested painting the stem with rust-proof paint.
I bought them from Henri at Moto-Science. Great guy. He was very responsive and helpful.