Hello,

I agree with you , having a direct PDF output could be wonderful !
But there's a technical problem : the general concept of txt2tags is to not 
have dependencies, and a pdf target would probably be wrote with the ReportLab 
library :
http://www.reportlab.com/software/opensource/rl-toolkit/
in the same way as rst2pdf :
http://code.google.com/p/rst2pdf/

By the way, the question is worth asking. I personally think it would be really 
great.

I've found this pure python recipe that can convert plain text to pdf (no 
dependencies required):
http://code.activestate.com/recipes/189858-python-text-to-pdf-converter/

Thanks for the link. This recipe is very limited , but works fine and has a 
good license (GNU GPLv2), so it could help a lot. But this would be a huge 
work. anyone ?

I think nothing can beat LaTeX for pdf rendering. 

But it's true LaTeX is huge to install. 

Instead of reinventing the wheel, I suggest to install wkhtmltopdf: 
https://code.google.com/p/wkhtmltopdf/ which can convert html file using webkit

You can get your pdf this way:
txt2tags -t html file.t2t && wkhtmltopdf file.html file.pdf

An other program allowing the conversion of html to pdf is weasyprint  
http://www.weasyprint.org