Your idea would make a cool widget. You might want to look into creating it.

If you wanted to manually create one. you will have to go to all the sites you want to put in your slide show and grab a screen capture from each and then input/upload these to something like slide.com or Photobucket.com

Good article. I am in full agreement on your initial set of consideration, especially personalization. It amazes me how many widgets out there cant be resized, remixed, colored, etc to suite the personality of who is using the widget. All of our yourminis widget have each element you outlined under custom options.

One other thing to think about when coming up with the concept of your widget is how it will be used. We are seeing that most widgets fall into two categories, consumption and expression.

People use widgets to consume content from all over the web (start pages, desktop widgets, etc.)

Others use widgets for expression (blogs, social nets, etc.). It is important to think about how your widget will be used, what your goal for the widget is and what is the compelling value proposition to the end consumer of your widget. When you can align these, then you have a good foundation for your widget.