svn://localhost and local username + port forwarding over ssh?

["chiasa.men" <ch...@web.de>]

Imagine:
svnserve is running in daemon mode. Is there a way to use the system 
credentials for access control?
So if user "bob" logs in and does a "svn co svn://localhost/peterRepo ~/" svn 
should check for bob and shouldnt ask for further credentials.

The same should happen when bob establishes a port forwarding mechanism over 
ssh to the svnserve port.

svn+ssh:// is not used, but svn://localhost.

(The reason seems to be that svn+ssh seems to create a new tunnel for each 
action (right?) while svn uses a persistent tunnel created manually/somewhere 
else)

Is this even somewhere discussed?