Career paths for teachers

In an interview with Education Week (paywall), 2012 National Teacher of the Year Rebecca Mieliwocki argues against traditional pay scale steps and columns.   Instead she prefers a model of advancement with a clear career path laid out, in which skilled teachers don't necessarily just go through the motions or become administrators.  As they become teacher leaders, master teachers, and veteran teachers (I think she was kind of spitballing with the names), they would have a different responsibility set and a different pay scale to go along with that.  She also talks about her position is not so different from the one espoused by the unions, unless one has a cartoonishly simple understanding of the union's position. (She's not as condescending as that, though.) 

I like the idea of having a career advancement path, but I'm also leery of who would write the rules.  This kind of change would be hard to get right, and the consequences on a school-level could be pretty harsh, on teacher morale if nothing else.  Hmm.  It will be interesting to see if anybody has already implemented something like this, and how it works for them.  Mieliwocki says that 90% of schools are run on the step-and-column system; I wonder what the other 10% are doing.