The reason we us fiberglass cloth besides the fact tha it wets out clear is because it has high tensile strength. If you want to compare silk to fiberglass just dig up the tensile strength numbers for each.
Also remember that the fabrics commonly impregnated with epoxy resin are all treated with special binder coatings to enhance the grip the epoxy gets on the cloth.
There was a time back 40 years ago when fiberlass canoes came out with tie-dye and other printed fabrics in their laminations. And I think similar stuff has been offered as an option in recent years.

: I got asked this at work earlier today. I have no idea how we got
: on the subject. Has any one incorporated plain woven silk fabric
: into their laminations (ie the exterior of a stripper)? On the
: surface silk should work: Silk IS one of the strongest natural
: fibers around and is very tough. It was used for early
: bulletproof vests and for parachutes. Laminating into a
: composite? No idea... I'm sure the surfboarders have tried it!

: I did some quick pursuing of the internet and it seems to top out
: at around 4.5 oz/sy. Cost: about $12/yard for 40" wide.
:
: http://www.plumridge.com/ProductDetail.jsp?LISTID=80000CB0-1196468281

: =D