How to generate realistic user alias names for testing reason?

Context

I would like to fill my application data with realistic test data. For many data items it is quite obvious (I can produce realistic distribution dates), for others (like first names, last names) I found points to start, but I am stuck with user alias names. I really want to have realistic ones (even I know that fname+lastname+ could do it perfectly in point of testing)

Question

I would like to have something what generates things like:

• badgirl
• BlueCream
• lordcyrix
• MrBeaumont
• babayaga

Note: I just do not want reinvent the wheel. If anyone has starter point where to get the vocabulary, or any other subpart of algorithm like divide a "bluecream" to "blue" and "cream" that could help