Outlook 2011 Conditional Formatting
I have not found an automated way to do what you are asking in Microsoft Outlook for Mac 2011. 

A (very) manual way would be to create a category named Read and assign it a color that contrasts well with black. As you read your email, categorize each as Read. Then the text of your read email would be colored to match the category color. Again, this is not the optimum way to manage email. 

If someone knows a better way I am interested to read it.