Wow, this should be a forum sticky—"Help with large-frame mixtes for Significant Others". Mine is 5'9", and I'm currently pinning my hopes that this CL is a 22" 1984/5 Le Tour.

The Buena Vista is v. nice, but a bit spendy for a second bike for her. However, I'm also eyeing the Public M3/8: http://publicbikes.com/p/PUBLIC-M3. The large size is a 55cm st/590cm virtual top tube (got them to send me the geo spreadsheet). At $750 complete and cromo steel, it seems a great value.