What a fun challenge!!
I think that the tubular trim you would want with quality nice enough for a bridal piece is created with horsehair. I have not tried this supplier, but here's a link: http://shop.mannys-millinery.com/sea...ywords=tubular
Also, my favorite millinery supply shop that I have used is Judith M. (Judithm.com) They have sinamay but no horsehair tubing.