Why don't we peer review our teaching?

I have to give a lecture in a couple of months as a result of getting a chair, which I have chosen to title "What Do I Know About Physics Education?". This morning, when falling awake, I found myself thinking about what sort of shape this lecture should have (...I have no idea how many people wake up thinking about such things but I would like to think I am not alone in this.... I vaguely recall something this morning about a thesis committee taking me out for Dim Sum as well this lunchtime. This, unlike the lecture, is a 100% dream....)

So, I was thinking : if the standard by which our research is examined and assessed is the peer review of articles, grants etc, why doesn't the same hold for the other side of the coin: our teaching?

I think that honest answer is that many places say they do this, but to what extent it is taken up I suspect is extremely variable, and likewise the spirit in which it is perceived. A quick and cursory Google brought up plenty of pages for institutions that ran similar systems to ours: a light touch Peer Observation Scheme. These examples included a couple I found in the US that used the process for formative purposes (ie for improvement of the individual concerned) and summative (ie appraisal and promotion considerations!)

http://www1.umn.edu/ohr/teachlearn/resources/peer/index.html
http://www.ncsu.edu/provost/peer_review/types.html

But it is of course impossible to see from the pages that details schemes closer to home just how they are implemented on the ground.

A page detailing a lunctime development session held at the University of Cambridge (..I wonder how many turned out for this ... and was it 'the usual suspects'....?). One of the speakers highlighted the importance of a 'supportive culture for teaching'. I think that for this to happen, the value and importance of teaching to the institution has to be (made more?) visible for all to see in all aspects of what is done.....