We've used this , and it appears to be as good as 3M.
http://cgi.ebay.com/ebaymotors/2-x160-Reflective-Conspicuity-Tape-Safety-Trailer-DOT_W0QQcmdZViewItemQQhashZitem1c0fd10f97QQitemZ120524443543QQptZOtherQ5fVehicleQ5fParts