I would really like to see this as it is very usefull. About two months ago I made a small library for stringslists using processes and a dynamic array to learn myself a vew basics of manual memory managment and pointers. My implementation is a bit crude and I released it under the zlib license, but normally I use the gpl/lgpl for my projects. I choose zlib because of it's permissive nature wich is conveint for libraries.
You can download it here: http://code.google.com/p/dykodialogs-for-bennugd/downloads/detail?name=dyko_stringlist_library.zip&can=2&q=
Just think of the possiblities: linked lists, dynamic arrays and hash tables are usefull for so many different things, like gui's, item managment, file lists, text search, you name it. Also a lot of languages have standard facilities for this, wich also allows for more robust software as it avoids manual memory managment.
I suggest implementing it as a library written in bennu itself, (wich should be possible) so that it's easily portable. A dll is less desireble as it requires knowledge of C compilers and build systems wich is something I dread. Anyway I really like the idea.