Accessible styled input type="file" and select boxes

Good morning everybody,

first of all I'd like to wish you a happy 2012!

Also I want to introduce myself with a few words.

My name is Marc Haunschild and I work for the Federal Office for 
Agriculture and Food (Bundesanstalt für Landwirthscft und Ernährung - BLE).

BTW: The messages I will send to this list represent my own personal 
opinion - they are NOT official statements of the BLE...

Main aspects of my work are accessible front end developing, consulting 
and quality management. The latest project was to assist and advise 
typo3 developers to make the general output of typo3 more accessible and 
to provide an accessible government package, which will be available in 
typo3 4.7 in spring.

About the subject of this mail: input elements with the type "file" and 
select boxes are dificult to style. Of course there are many solutions 
out there, combining css, javascript and other HTML elements. Most of 
them have accessibility issues. As a matter of fact, I do not know, 
which technique to use. And I have tested really a lot of these 
solutions...

Does anybody has a personal favorite technique?

Thanks for help!

Marc