[texhax] Local search path

[Thierry]

Hello,

I have a big project with many files. 
I would like to create subdirectories by file types:
- style files
- pictures
- chapters
- ...
and only keep the master files in the main directory.

Is there a way to tell pdflatex to search for files in these directories WITHOUT 
making explicit reference to the complete path in the \input, \include and 
\usepackage command?

I known that for picture files it is possible with the command
\graphicspath
from the package graphicx

What for .sty files and .tex files, and any other files?

May be I could play with a texmf.cnf file to add some subdirectories: 
"pictures", "styles", "inputs" etc... in the TEXINPUTS variable.
But I don't know if I can create a local version of such a file (in the main 
directory, in my texmf tree?) and what is the correct syntax to use.

So I ask for advises and comments
Thanks in advance
Thierry