The QSignoff folder uses a lot of disk space, can is be pared down without issue?
It's a folder used for Microsoft Error Reporting. Per this MSDN article:
The signoff queue is used for reports that the user has not seen before. Ship assert reports are sent to the signoff queue.
Signoff queue CAB files and instruction files are stored in this folder:
%USERPROFILE%\Local Settings\Application Data\PCHealth\ErrorRep\QSignoff
If you don't want to do anything with the error reports you should be ok purging the files.
Here's another MS post that is a bit less wordy than the MSDN article. A snippet from the post:
You can safely delete these files. QSignOff folder and the contents of this folder are related to Watson report. Whenever you hit any application crash, Watson will collect the memory dump, stack trace and other relevant info. These data are stored in QSignOff folder. So, these files are not interesting if you had sent the report to Microsoft.
These are the "Administrator queues" used by the "Microsoft Error Reporting" service (see http://msdn.microsoft.com/en-us/library/bb219076.aspx). It sounds like you're seeing a client computer that isn't shipping these files off to Microsoft (these are related to the "Error Reports" that users can opt to send when they see errors in applications) like it's supposed to.
W/o going into a long research project, my guess is that you can blow away those files w/o any consequence. I'd consider disabling the "Microsoft Error Reporting" feature via Group Policy (Computer Settings - Administrative Templates - System - Error Reporting).