For detailed information regarding each part of the Boba Fett Concepts costumes, see Boba Fett Concepts Costumes Details
From the Empire Strikes Back Sketchbook
"While most of the film's costume design originated in England, Ralp McQuarrie and Johnston designed the Boba Fett outfit at Industrial Light and Magic in California. The costume was built at EMI in London, and then shipped back to Johnston to be painted. Originally the Boba Fett costume was intended to be worn by a squad of supercommandos, troops from the Mandalore system armed with weapons built into their suits. But the costume was adapted for the Boba Fett character by aging, denting, and adding a colorful paint job to one of these suits, while keeping the wrist lasers, flying backpack, and rocket darts originally intended for the supercommandos."
Call, Deborah. The Art of Star Wars, Episode V - The Empire Strikes Back. New York: Ballantine Books, 1994. 138-140, 144-146. Print.
The Art of Star Wars, Episode V @ amazon.com
Johnston, Joe and Rodis-Jamero, Nilo. The Empire Strikes Back Sketchbook. New York: Ballantine Books, 1980. 69-71. Print.
The Empire Strikes Back Sketchbook @ amazon.com
Additional ReadingConcept Art for Boba Fett Costume @ thedentedhelmet.com