Actually I think I found the amazon.CA version of what you are referring to.
https://www.amazon.ca/gp/product/B002JTR9P4
Not sure why I didn't catch it when I did a search for RCA or Coaxial cables. But anyway, Thanks. This should serve my purpose.
However, had this item not been on sale, using speaker cables would still be more economical. In that case, could my original plan work? Would there be any problem in using CL3 speaker wires with RCA connector crimped at the ends for subwoofers? Cheers.