Free Virtual Singer
I'm currently writing a free Virtual Singer that replaces VOCALOID and UTAU.
http://packages.debian.org/de/sid/jcadencii is in Debian unstable, but I do think it can't be included in Trisquel because VOCALOID is nonfree.
The free software that I wrote is at http://gitorious.org/lauloid
A free voicebank is at http://platen-software.de/mbroloid/
jcadencii will be in the next version of Trisquel.
jcadencii is designed to use proprietery signal processing engines.
It allows Mac users to run some proprietery Windows programs on Mac OS X with a Mac GUI.
There are some free signal processing engines such as praat and efb-gw.
efb-gw is buggy and sounds bad at higher pitches.
It is also nice to have a free recording tool for voicebanks.
OREMO is free, but it does not run on GNU/Linux.
I bet those Tsurunen wavs could be archived better with FLAC than with by zipping them.
Some free resamplers only support wave, so I do not FLAC them yet.
Later versions will use FLAC.