Jazzy, if going with fret-lines in place of frets, *definitely* go with wood instead of plastic or fibre purfling... get something as close to ebony in density as possible. The fingerboard will expand and contract seasonally at a different rate than the inlay, which can cause some buzzing issues. I'm pretty sure (and if she can, please correct me) Mica said they used white holly for the sidelines on my Custom.
Be aware also, pearl inlay is problematic on fretless basses... the notes will land between the inlays, and that little bit of string travel is going to sound odd as the string oscillates against something other than wood. I'm having a hard time remembering your Bocate Europa, but I seem to remember the double-P Elan did have pearl (oid?) oval inlay.
If you're set on a fretless bass (and I
loudly applaud the idea, especially for you...

) perhaps a trade may be in order.
Good for you, man. Frets... pfft. Who needs 'em?
