A extensions for Chrome only needs a few files:
Read the Getting started tutorial for more information about developing extensions.
I made a little demo extension with the use of JQuery UI for some eye candy and just to see if it works. Good news it does! Bad news too some extend. You can down load the zip file or view the source online.
I haven’t fully tested all widgets jQuery UI provides yet, but I can tell you there are some issues with the accordion, you need to set autoResize to false for it too work, Dialog doesn’t display properly in a popup since Chrome does not resize the window if needed and I noticed some issues with the Datepicker in a popup aswell.