(nettipäiväkirja 25.11.2014) I just realised it might be worth advertising in English that I've implemented multiturtle/dynaturtle functionality for UCBLogo. I've been searching for the documentation of UCBLogo's experimental object system and this seems to be something of a FAQ...
The implementation is pure Logo but quite fast anyway. It's available at:
https://github.com/atehwa/ohjelmointikerho/blob/master/logo/maailmat/turtles.lg
There are also a couple of other oft-requested features in the same folder.