where can I locate concrete stair treads?

Answer 1

You are talking about a embedded stair nosing right?. I always order them from a local metal fab shop. Anyone that does handrails should also have them. I am sure they order them from somewhere else, but they could do it. The people that fabricate them may not sell them directly to you.

Look here
http://www.balcousa.com/balcousa/index.cfm
or
www.americansafetytread.com

Answer 2

Try your local carpet outlet. I got some through the guy that supplies the carpets here at the school I work at.