Hi Florian,
I haven't rolled out 7.40 myself, but a while back I wrote a document series on setting up Installation Servers for 7.30, and as part of that I included instructions for using shared central configuration files (saplogon.ini) instead of distributing them to all the users.
One of the folks commenting on the blog came up with and published in a comment how to do the same thing for 7.40, and I believe this can be adapted to your situation: SAPGUI Installation Server Part 5 - Scripting.
Cheers,
Matt