It's true: sil nylon colors are limited to gray and what's left of earlier dyelots.
It's a really troubling time for the textile industry both here in the US and abroad. The sil market has been in disarray since the epa lawsuit that shuttered the Duro finishing plant. Much of the supply, even 1sts, these days is of questionable adequacy for backpacking canopies, as the hydrostatic head pressure has been impacted by the changes in the finishing process. These changes apparently don't impact it's primary application: parachute canopies.
In order to keep up the specs to what I think is adequate I have to run dye-lots, and because of the high yardage requirements I won't be running anything but the most popular color (grey) going forward.