As it turns out, Chrome's extension environment is 1.28 billion times easier to use than the environment in Firefox, so porting the code over is much easier than I anticipated. I may even have an initial version for Chrome by the end of the weekend. :-)

After messing around with it for about 4 hours this evening, I was able to get the tools to draw and a dummy signature to insert in Chrome. The only thing I really have left is to create overrides for the Firefox functions to store and get preferences and handle the processing of locale text. After that, it's just a matter of updating the options window for Chrome, and we're all set.