I am posting the solution I found, I hope it might be useful for others.
I found a third party service - GrooveUI.com. They provide a UI for creating multiple themes for a website. The theme are enabled based on access URL.
This is close to what I was looking for.
Thanks.
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Hi,
I am developing a SaaS based web application. My requirement is that all my users can have custom look-n-feel of the application.
Are there some standard tools to implement this.
I know I can write server side code or use javascript to update CSS and Images during page access. But is there anything I can use off the shelf?
If this question has already been asked, please point me to it.
Thanks.

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