authorization with svn+apache access

Hi all,

Are there any better ways to implement authorization with svn+apache apart
from authz and basic http authentication?

I would like to following unix permissions similar to file:/// using
svn+apache as well. In this model we will be running httpd as a normal user
and the user will become other users (using sudo) based on the USER variable
and proceed with svn operations. I can think of hooks scripts, but I'd like
to know what is the master program which does all these svn operations (e.g.
commits, hooks scripts executions) so that I can wrap the master program.

Please let me know your suggestions.

-- 
-- JNR