From March 10, 2010 it seems.
This was before they recently announced Cassie would be back as "BlackBat" part of the Batman Inc. concept.
'Thought the blog could use some more of my own drawings :P
- " 90s Batgirl Cassandra Cain teaming up with the current Batgirl Stephanie Brown! :'3
They both kick ass and I am still waiting for this team up to happen in the books! Do you hear me DC/Dan Didio/Jim Lee? Make it happen!! >__<"