Found a very useful website for generating Dynamics CRM Themes.

Click on the link to see the below page.

We can choose different colors for all the important elements (Right hand side) and see the effects immediately (Left hand side).

Interesting feature is that, we can export the required Theme data to an excel using Export Theme button and can import the same excel to the required CRM organization.

Hope this helps and save lots of time in creating Themes :):):)