Thread finally updated with all the information gathered last month. (Actually, I have moved that entire conversation here as it's full of good stuff). Thanks to all for your help. Please let me know if anything needs to be fixed.
Because the MentorGraphics site (where you can get the CodeSourcery toolchain) is such a huge pain in the ass, I made an open document on GoogleDocs containing the download links to all versions of the toolchain (which should work without login information, they just don't give you the links until you ask them).