I think various different trainers in the personal development scene can hold seminars that significantly change a person's psychological toolkit in a matter of weeks.

Even if you can't create an environment of similar strength, there no real reason why you can't take David Burns Feeling Good Handbook and teach the material to children.

But teaching kids how to be happy alongside the normal curriculum in the usual state school setting may be asking too much.

The normal curriculum is broken. Most schools are places where a variety of factors prevent student from being open about their emotional issues. If I'm being graded on me own written investigation of a uncomfortable belief I'm unlikely to open up and tackle things of which I'm really afraid.

There no reason to teach student to interpret poems but not skills like dealing with their own limiting beliefs.

Has it been tried anywhere to your knowledge?

In the UK there push to do things like teaching happiness:

Under the Birmingham initiative, emotional well-being is being made one of six priority outcomes in the authority's schools, which teach 180,000 youngsters.

The article lists as criticism:

A Scottish charity which drew on 20 international studies warned the classes could blunt children's competitive and entrepeneurial edge by placing too great an emphasis on avoiding hurting people's feelings.

Of course if your goal is to avoid hurting people's feelings you are unlikely to get very far. You don't want an enviroment in which no child cries but in which it's okay to cry and the person who cries is supported.