From ICM perspective you will need to modify the MaxTimeInQueue registry setting on your router in HKEY_LOCAL_MACHINE - SOFTWARE - CiscoSystems Inc - ICM - - RouterA/B - Router - CurrentVersion - Configuration - Queue
Also the MaxNodeThreshold in the same tree but Script folder if there will be enough loops through your PM/VXML RunExtScript for Hold Music to trigger that threshold
I am not aware of any UCM or CVP settings that would have an effect. IF this is UCCE.
Ryan provided very good information. As you can imagine, those who use the Email channel queue calls for days in the memory of the Router.
Be aware that it is possible to limit the registry setting mentioned above by setting values on the Media Routing Domain. Not normally done for voice, but on Email I make this slightly smaller than the registry setting.
If it's possible, could you say more about these 100 calls queued for 5 hours? What is on the other end? ;-)