OK
Here are four sets of MicroStation Linestyles in DWG files. There are designed to be used with AutoCAD line types for scaled linetypes via annotation scale, MSLTSCALE, PSLTSCALE, LTSCALE all set to 1.
They should only be used to represent real world objects, using a linetype scale of 1 when placed.
These come from our local State DOT's Highway Administration. They are used to represent real world objects, placed at actual size. Pipes are created using the width, in feet, of the ID of the pipe.
Let me know what you think and how they seem to work for you.
BTW, as I understand it, they create objects in the file that a regular purge apparently cannot remove. There have been posts about this and on some blog, someone posted a custom tool to allow one to fully purge all remnants of these once they are not being used.