I have neen on the NVQ 2 course that Impact do and althought you do learn some interesting points, especially about H&S it was more geared to extreme heights. Domestic and low level cleaning was not really covered.
There was also no practical training on the glass, they did access me on one of my jobs which was a school with difficult windows to clean and H&S issues, at one point the did a video of me cleaning some windows at 60' using a SL2.
There are a lot of collages that do offer courses on cleaning and window cleaning is a module of the course, they also learn other aspects of cleaning as well, most of it though is classroom based and they would like the student to gain the practical on the job with an employer.
Personally I do not think that there are training schools that offer practical on the glass training, I might be wrong though, but if there was a course on this, would they train the student in how I want the job and clean to be done, like you I feel, I have very high standards and I do not think that a training course by a 3rd party would teach this to them.
If you clarify what you want them to learn maybe, some people on here can come up with suggestions or ideas that you can work with.
William