Contact Joe or Mark Stevens of Stevens Magic Emporium (http://www.stevensmagic.com
), as they have gimicked jackets for sale (by Viking).
John Novak (who was my mentor) got me started in escapes more years ago than I care to remember. He wrote a series of books on escapes, one of which was on the strait jacket. Joe may still have those in stock. You might email him and ask.
I did the strait jacket both suspended upside down (now that I'm in my 50's, that really doesn't appeal any more) as well as standing on the "stage."
Good luck, and if I can be of any help, drop me a line.