This Excel utility does not actually edit QSD files but it does read them in a format which will make sense to you.
Required:
Microsoft Excel
comdlg32.ocx Some computers do not have this installed
Make sure your Excel security is low enough to allow macros OR put the file in a specific folder and set that folder as a "Trusted" exception so that macros will always be enabled from it. (excel 2007 only)
Instructions:
Click the QSD tab
Click on the button at the top of the page labelled "Load QSD"
Navigate to your chosen QSD file
Click "OK" and it will parse the file, decipher it and display the results.
With a little work, this utility could also be made to save QSDs. Just be careful if you plan to modify it.