Also relevant to crafting Steelsilk armor:
Pardas Nalue in Paineel should sell Platinum+Gold+Silver Threads. He currently does not.
August 10, 2001 EQ Traders: https://web.archive.org/web/20010810.../tailoring.htm
Kamzar in West Cabilis should also sell Platinum+Gold+Silver Threads, and interestingly, Erudite Sewing Kit and the book On Terrorantula Silk, according to the same link above. He currently does not have these items for sale. There are more items he should have also, such as Small Sewing Kit, all clothing patterns, etc.
EQT also cites a "Erudite Sewing Kit," rather than the "Worn" Erudite Sewing Kit that is currently on P99. I haven't found evidence yet showing there is a difference between the two containers.