Ututo

http://www.ututo.org
https://en.wikipedia.org/wiki/Ututo

Still very much alive, but now mostly based on Ubuntu
(that's the Ututo UL variant)

Citing from the homepage, via Google Translate:

It is an Ubuntu 64 iso, to which the packages and non-free 
repositories were removed and the nucleus replaced by a free one. The
scripts for doing that task are here.

The idea is to serve the original purpose of Ututo: distribute 
Simusol. And of course keep your two characteristics relevant:
* Operate without installing in an extremely simple,
* And be 100% free. 

The aim of the project is to encourage and promote the generation and
appropiation of knowledge in developing countries, reducing the (so
called) digital divide.

In this opportunity, after a two-year break, the Ututo project meets
the presentation and distribution of the free SimuSol software.
SimuSol facilitates the description and simulation of different
physical circuits and their numerical simulation.


The original version (?) and for sure the XS variant were based on
Gentoo, as was probably the desktop variant Ututo-e.

The last release of the XS variant was 2012.04, not sure about the e 
variant.