I can't answer any questions about stitch density or suppleness of quilted item, but the only times I have seen osnaburg mentioned is in Nannette Holmberg's books on making faux chenille quilts and garments. That gave me the impression it frayed easily.
I have seen Thermore by Hobbs suggested for use in quilted vests and jackets. It is advertised as non-bearding, for "fine, quilted projects", and hand or machine washable. It is resin treated polyester fiber.