need specific functionality for expanding zip files

[tech_ed]

OK...the scenario is I get zip files from my web developer. These files either add or replace existing files to my already functioning web site.
The zip files have all the new files in the directory structure that also exists on my web site. I just right-drag the zip file onto the correct directory and it will add/replace all the files beginning from the root directory I drop the zip onto.
Here is the problem though.
When a file exists in both the zip file AND my website, the un-zipping will only allow me to overwrite or cancel. What I would like is the ability to back this file up or rename it with a .bak extension added to the file...
optimally though, what I really want is a zip program that has an "un-do" or an "uninstall" feature so that I can backout of the files replaced...

Does something like this exist? I can certainly write a batch file that will do this, but I'm really lazy and if it already exists, then why bother?

Thanks
Ed