There are quite a few textured plastics.
I just looked through the samples I have
and didn't see anything close to that
pattern. I would try a plastics distributor.
The best one I know of is here on the west
Coast-San Diego Plastics, I'm sure if you
Email them a pic, they may be able to
point you in the right direction.
On the issue of ADA, generally these signs
do not require Braille or tactile. It does not
stop sign shops from doing it though. An
occasional rogue inspector not familiar with
the code may demand it.
On larger jobs I usually run the design by the
inspector so I don't get any surprises during
sign off.
Since they are usually back of house, most
designers and sign shops specify cheaper
materials.