Hi,

> hm, dunno packages that well -) does this mean that one macro has a whole
> package?

sometimes there are two or even more macros inside a packge! But that is 
the way LaTeX is: a small kernel with no changes in the last decade and a 
great number of additional stuff which is packed in packages. So you 
sometimes have pages of \usepackage{...} statements :)

> What do others think? Which one is the nicest for default (i opt for the
> (as usual best) third one, so that one goes into core-mis.tex and will
> end up in the documentation void -)

well, I don't like any of those. The spacing in the last two is too tight. 
The first one is kind of ok, but I'd choose a smaller / 

\def\textfrac#1#2%
   {\hbox{\tx\high{#1\kern-.15em}\raise .2ex\hbox {/}\low{\kern-.15em#2}}}

 test \textfrac{1}{2} test \textfrac{123}{456} test

This also comes close to what my favourite typography book says. I don't 
know if the def is bulletproof against other fonts/setups. 

-- 
Viele Grüße, 

    Patrick Gundlach