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I don't know of another way in GWT but you can do it in CSV format in SEOmoz tools.  I know that SEOmoz 404's is different than what you probably see in GWT but you can run a on-page report and then download the CSV report. Sort the report to show all the 404 errors and in the last column you have the referrer.

I was really looking for examples but thanks for the response anyway.

Yes i think you are better off putting your time into fixing the canonical tag on the server side. It may even look sus doing what you are doing. I would go to WMT and view as google bot and see how they see it, i think they will read the tag before any js.

There are certainly a lot of worse things you could do than follow this guide by Oli Gardner - http://www.seomoz.org/blog/the-noob-guide-to-online-marketing-with-giant-infographic-11928