Not sure if you found the belt you were looking for but PRB Line was a company that supplied VCR, turntable and tape deck belts.
http://www.a1parts.com/belts/prb_rubber_belts.htm
I know it's way out of you way but R-VAC electronics who moved to Monrovia (I think) used to carry a good stock of many of the belts. Another local electronic store may also stock them.