Great idea!! Rated 4 out of 5 stars
I noticed that the results won't show up when I have XMarks search suggestion icons showing next to the Google results. May be a formatting/space thing.
Otherwise, working well. I'm hoping the implementation will improve slightly over time to deal with other add-ons and the window size, but overall, it's great!
Google is getting quite crowded with different extensions ;-) Version 0.5 should be compatible with Adblock Plus and Googlepedia and the window size problem should be better now too. I will try and get a fix for XMarks into the next version. Check back here for the updates as experimental add-ons won't update automatically. Please let me know if there are other add-ons that cause problems.
UPDATE: Version 0.6 should fix the compatibility problems with XMarks. There is also a new option to adjust the position of the XMark icons when the Wolfram frame is showing.