Pora had asked for sources for bra stuff recently so here are some more--- all from the New York garment district. I found these in Threads:
J&M Textile
315 W. 36th St. NY, NY 10018 (212) 268-8000Guide Fabrics
262 W. 38th St NY, NY 10018 (212) 575-8855Those two carry interfacings and other support fabrics. The other one carries underwires, bra cups, boning, etc.:
I have not personally tried any of these three as yet. I may phone the first two for catalogues.
Phae