Edwin,
To answer your question: No, there is nothing else of comparable value. I don't have any myself, but I'm pretty sure I understand - in comparison, everything else is merely nice, at best.
But those are a couple of really cool little basses. I'm a little surprised Alembic hasn't featured anything quite like this, because it really shows just how far they'll go, and I can imagine the care, and joy, that went into making them for your daughters.
Maybe you should get them to chime in on the thread about how old were you when you got your first Alembic?.
-Bob