Might talk with our member Mac Irvin, he has a source for making molded urethane parts....If you are looking for something extruded like windshield molding than, "WEFCO" may be your best bet.
WEFCO Rubber Mfg. Co.,Inc.
21000 Osborne St. Unit 2
Canoga Park, CA 91304
Phone: 818-886-8875
www.wefcorubber.com
What are you looking at making? As a thought they make a two part urethane seam sealer that comes in a calking tube that I have used when in a real bind.