The solution could be a 5V power supply module made like the Power
Supply module in the portable cases. It could be sold with a beefed
up buss board to replace the installed one (but then there would have
to be a AS and Doepfer versions) or it could just connect directly to
the modules with molex connectors (the classic PC power connectors
would work). It would plug into the additional AC connectors that
Dieter mentioned or in worse case scenario there would be a front
mounted IEC connector like the Portable cases. You would have to
mount it at the end of the row and the it would only want CV type
modules next to it but it would be the most elegant solution with the
least amount of user involvement (at least the direct connect - no
buss version).

-James