Moving some old feature requests over so they don't get 100% lost. :D
Seems like this was a request I made a very long time ago, but it's still very much valid as it's a very highly sought after feature for many users bases.
Having vector layers/tools for clean line work is a corner stone for many Manga/Anime/Comic/Layout/Design...etc artist.
The complexity of the vector tools dose not need to be on the same level of Illustrator, or inkscape. Though given it's powerful dab style engine TB could do some amazing things if it used a vector system similar to Clip Paint Studio. (eg: Drawing brush dabs along an edible vector path. Which gives you the ability to have the benefits of the precise long term editing potential of vector paths/lines with the visual look/result of a raster graphic.)