Originally Posted by
DrIsotope
What someone needs to find out is, what actually is tubeless tape? It seems to me unlikely that it's cycling specific-- somewhere out there, you can buy massive 500m spools of beige plastic tape @ 10¢ a meter, because it's for pipes or flanges or something industrial/scientific.
Two answers--
1) a suitable substitute can be found in Kapton tape, used for insulating purposes in electronics.
2) 3M 8898 strapping tape is the most likely culprit, though other companies surely make an equivalent product. It's still fairly expensive, even buying by the roll, and only available in a handful of (immediately) useful widths. The tape cuts easily, but it can be a pain to get "right", with the edges of the tape going straight up to the sidewalls of the rim.