Or Mercedes-Benz E55T, or BMW 540i estate...there are a lot to choose from.
Actually I looked at the Audi US site and it appears that you guys don't get the RS6. Shame.
http://www.audi.com.au/content/Model.aspx?s=571
If 0-62mph in 4.7 seconds isn't quick enough to get the kids to school, then you can opt for the 'Plus' version. After that, you're beyond help...talk to Brabus about an EV12T.