It will be interesting to watch how it evolves, did you consider creating a new entity?
Having been through the process three times now (on the side of the startup, not the firm) its been interesting to evaluate the different focus and people who populate the later stage companies from the early stage companies. Clearly the questions and metrics are different, but I've found the engagement to be different too. Much more bankerish and less advisorish if that rings any bells at all.
I think YC changed the early stage game in a fundamental way, much better than Angels it has the whole network effect of both Angels and every company that has been through the program. I guess I'd like to challenge you to be more innovative as a late stage investor than announcement seemed to suggest.