As a followup on this post, I found some of the tools at door2windows.com come in quite handy for changing system resource files.

The most versatile program is CustomizerGod which changes most of the common files you'll find in the theme packages here. Including timedate.cpl and shellbrd.

The only thing it doesn't change is the system.cpl . I haven't found any programs on their site that will, but I have to say CustomizerGod is one versatile utility.

You can find direct download links at the bottom of download pages.

Also, if you like their programs please consider donating.