Integrated learning is a sure fire way of making the links between seemingly abstract skills and ensures that higher level thinking skills are developed and clearly demonstrates how no school subject is discrete from the others, giving increasing relevance to them all. I say this from a Maths teachers' perspective where you are always being asked why you have to learn algebra, times tables or Pythagoras? Showing how these skills are useful in other subject areas has got to be positive for everyone and can even improve employment choices.
I'd be interested to know what schools are already doing in terms of integrated learning or what they would like to do given a bit more time. Planning with teachers from other subject areas is even more time consuming than collaboratively planning within your own department as there is all the background stuff that needs to be covered first. It can feel like you've spent 6 hours planning a 30 minute lesson so you've really got to believe that the benefits to the pupils outweigh the disadvantages before you even begin. Like most things, it will get easier with time, but for teachers who are already pushed for time and under immense pressure to reach targets it might be that the idea of integrated learning is just something for another time. If you've got an idea you'd like me to develop let me know and I'll happily do the research for you and come up with a series of lessons to meet your needs and in return for you trialling it in your own school there would be no charge.