Hong Kong have several sailmakers. You can buy cloth, zippers, basting tape, thread, needles etc. there. Or you can import what you need from any foreign sailmaker or Sailrite in the USA (www.sailrite.com).
If all these fail, let me know and we can work something out.

The cheapest solution is to break out your sewing machine and cut your panels yourself. Just the experience is worth the effort, and the result _will_ look and set like a jib, no worries. Sailmaking is not rocket science (no matter what North and others say), but an art and a craft everybody with the inclination to can master.
If you want to go into mass production, that is a completely different matter.