The "replace robots" feature is back at World of Card Games. You can use it to start a game with bots, and allow humans to replace them as they arrive. Details are in this blog post.
This feature was first added on January 13 2014. But after several hours of good behavior, the site crashed. So I pulled it back, and worked to figure out what went wrong.
I tried with a new version on February 12, but it caused the site to crash too!
This time, I'm pretty sure that I know what was going wrong. With the bug fixed, I think this new version will work correctly. Is this third time a charm? I hope so!