Hallo,
for ''perfect german'' there is a package hadifix which i used a lot since 2-years for a automatic web radio anouncements.
http://www.ikp.uni-bonn.de/~tpo/Hadifix.html
My suggestion: I found mbrola is a pvery good voice synthesizer and hadifix uses it. the work before so maybe we should just implement mbrola as an object and use any text to phonem processing elsewhere like in shell-scripts, since mbrola is good fun also for singing voices... and each project needs anyway its own filter scripts. (like web news or emails to speech).
mfg winfried