I have been working on the FlashResizer Bookmarklet for a while now, and I thought of converting it into a Google Chrome extension. Here is a video of the functionality of the extension.
This extension is still a work in progress and I am working on ironing out some non-critical issues. The extension has been submitted to the Chrome extensions Gallery and is pending approval. If you would like to try it out, you can download it from here and open the .crx file in Google Chrome. Chrome will ask you for confirmation at the bottom, and once accepted, the extension should show up on all web pages containing flash movies.
You can watch out for updates here. Please do drop in your feedback as comments or contact me. Any offering to help with the development of the extension would be great too :)