Not that it helps you but the Kindle uses
Nuance Vocalizer Embedded for its text to speech. There are several large voice data files in /usr/share/nuance/data and /usr/share/tts/dict contains the dictionaries. 3.1 added some extra dictionary files so the TTS should in theory be better sounding.
Your best bet for a replacement TTS daemon would be basing it on something like
Festival-lite or the full version of
Festival. I'm unsure how good the support is for non English languages. Festival-lite only does English and Spanish by default. Festival is more flexible and can support more. Neither really sound that amazing however but its free...