Sai has become my primary art tool as of now, I use photoshop mostly for special effects and original texts and such.

But Sai has one serious flaw, it has NO shape tools. Now I don't know if I'm just not noticing them, but not having a straight line/Shape tool means I would have to jump between programs for comic boxes or background elements BEFORE I even have the finished product. Does anyone know of a plugin or patch that includes shape/line tools that can be uploaded?