Alternative ways of "lining" a fretless fingerboard?

[richnota]

I'm discussing approaches with luthier Rob Allen (he's putting lines on an existing bass' unlined neck for me).

There are some inlays a previous owner put on the side of the neck (mother of pearl markers) that may interfere with the standard approach.

Beyond the obvious method of cutting slots/insert line material/sanding, are there alternative ways to put lines in?

shallow slots? dye?

the board is ebony.

[Darkstrike]

If you don't necesarily need full lines, you could have him drill for dots under a string, you would have the marked board, but still be unlined looking from the front.

Like this.

[mynameisandyb]

One way I've seen someone do it which I quite like, is only doing the lines for about half an inch across the fretboard (on the E side) an even running over the neck a bit.

Also, I've seen only having fret lines on the dotted frets.

You can have a vine of life as well.