I would recommend persevering with the sourcebans
hackmodule for ULX, ill go fetch a link...
Sure, it moves the issue to a different place (struggling to make sure all your admins have access to sourcebans), but lets compare it...
Before: Struggling to ban up to 20 minges a week on 7 servers...
After: Struggling to ensure (lets say 8 staff members per server, 1 being the same across all servers, puts us at 7x7 = 49 + 1 = 50) 50 staff members have access to Sourcebans on a permanent basis, and ensuring you remove them after you demote them...
It may not sound like it, but Sourcebans actually will reduce the effort required, unless you make a universalban command which before banning from server A, it proceeds to send an RCON command to the other 6 servers to ban the players SteamID for the time specified (I say before because you want to catch his SteamID and use it for the RCON commands first)
EDIT: Use this tutorial:
http://forums.ulyssesmod.net/index.php?topic=5875.0