Eric, It appears the vest fabric is still good, yes ? If so can you sew, or
know someone who does ? Fabric stores and/or online shops sell sew-on
reflective trim/tape sold by the yard/meter. It need not be placed where
the other tape is either. FWIW, some fabric adhesive like McNett Seam Grip
I can't help you on the Mavic vest. My LBS carries a brand of vests from
Belgium called Go Fluo.
https://gofluo.com/product-category/sale/?v=7516fd43adaa Happy-Go in DC
is also a Riv dealer. Give Ben a call and he can tell you what items he
has in stock. https://www.happygobikes.com/s/sho