Ah, looks like you truncated the "6" off the end of the first version my command line then appended the March 17th update!
Well forget all that anyway, now an even more updated command for prettier output (collaborating with Rixstep):
curl -s $(strings /System/Library/PrivateFrameworks/SoftwareUpdate.framework/SoftwareUpdate | grep http | grep sucatalog) | grep Safari | grep pkg | sed -e s/"<string>"//g -e s/"<\/string>"//g -e s/\ //g
Your results should look something like this, it includes Safari 5 and 6 links:
http://swcdn.apple.com/content/downloads/18/14/091-9898/opy4mtpobcg21e1xj2l0uy9a yvq2ys59zs/Safari5.1.10SnowLeopard.pkg
http://swcdn.apple.com/content/downloads/03/59/031-2518/8hyvmyua1d8wmr8oy6s3wb6e 17a1cbj46j/Safari6.1.1MountainLion.pkg
http://swcdn.apple.com/content/downloads/51/43/031-2516/azk33bwf7brw2f6sjh9swwkq 736dbkonwe/Safari6.1.1Lion.pkg