Digging around in our library I found an interesting report from the Institute for Complex Engineered Systems at Carnegie Mellon University on Design for Wearability.
This research has been done ten years ago and is a excellent guide for designers, students and hobbyists who want to find the best place to integrate technical elements into clothing.
The ‘Design for Wearability’ study (link to PDF document) was conducted by Francine Gemperle, Chris Kasabach, John Stivoric, Malcolm Bauer and Richard Martin contains a excellent analysis of different locations on the human body for the most unobtrusive placement of wearable objects.
The team worked out thirteen design guidelines and possible shapes of wearable objects to ensure the added technology does not compromise the wearability and dynamics of clothing but to enhance it.
I can highly recommend to anyone interested in designing interactive clothing to have a look into this document before starting a new design.