A scarf made with matching wood is nearly invisible. Worst case, it doesn't create a more visible line than butt-jointing does.

Brian-
You're more skilled than me, I suspect.
Scarfing thin (3mm?) plywood with its paper-thin face veneers is a challenge for me.
Getting the ends square and aligned is difficult enough; I also find that the epoxy (I use epoxy for this type of scarf, perhaps a PVA glue would be better) discolors the joint edges.

I'm always keen to learn, though. Do you have any hints and pics to share?
Thanks!