You know that you can use the ACAD.lin file in TBC and that you can edit all of those in a Text editor right? I often will start there as the Text Editor allows you to embed real text in the linestyles rather than have to draw them all as lines - and if you like a line file from AutoCAD or from imported DWG files, you can add them to your master library pretty easily.
I don't disagree that the editor is a little dated
Alan