I've created a new edit-in-place plugin that is a modified version of Dave Hauenstein's. It allows for selects that are generated at the point when the editor is created, rather than on page load, as well as the option to switch the select to an input box for adding values not currently in the select. It also has integrated datepicker functionality. You can download it at:
http://code.google.com/p/dynamic-select-edit-in-place/ I make no promises to the overall quality of the code, but in my testing it works in Firefox 3.5.2, Safari 4.0.3 and Internet Explorer 6. I've created this primarily for my own purposes, but since I was unable to find a plugin that had this functionality I thought it would be worth it to share it with the community. I can't promise that I'll update it a lot, but I may, and at the least it can provide a jumping off point for someone else.
