Mapping Center Answer:

ArcMap does not, by design, support what you are seeking to do. We used to do that with ArcView GIS, and found that a number of our customers created documents that were very large (100s of views and 1000s of themes) to manage, and when something went wrong, they lost a large amount of work in just one unfortunate episode.

If you have some sets of layouts that are essentially the same (titles, page numbers, etc. change, and the fundamental layout does not change significantly), then look into using one of our developer samples called ArcMapbook (originally called DSMapBook). It is available at: http://arcmapbook.sourceforge.net/. The maps in your maps series can be of any scale or extent, which answers your primary question. Much of the information that ArcMapBook uses is not actually stored in the .MXD, but in a feature class, so an additional benefit is that the risk to loosing work is much mcuh lower.