I'm thinking the undersuit pants are either some sort of kevlar jeans/pants, or oilskin pants.
Kevlar 3M black coated biker pants Limited - Pants - Collection
http://www.smartcycleshopper.com/motorcycle-news/aerostich-offers-new-falstaff-pants/
I got a feel it's some sort of motorcycle...
I was actually thinking of casting plastic swords from my Island Slade costume, but I don't know if I'd be able to sell them. I'll check around and let you know.
We appreciate it man! You guys did great work! The suit is so iconic and as a hardcore fan of Deathstroke in the comics, i love the direction you all went with the live action suit. I think it's awesome that you are so willing to help us all replicate it! I can't wait to see more of your work in...