J.C. Whitney has some 3/16" here, or you could have a look at Restoration Specialties, this is a link to a catalog in PDF format, go to page 110, P/N 188FW which is 1/8". And lastly, Metro Molded Parts has some 1/8", P/N LP 15-C in rubber or LP 16-C in vinyl.
That should get you started
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