Doug,
Thanks for your reply.
Here is what I got to work, which also may be what you are suggesting.
I created an MXD that contains our 1969 imagery and set the "Extent Used by Full Extent Command" in the Data Frame Properties to an extent that is similar to the full extent of the 2010 imagery and that is much larger than that covered by the 1969 imagery.
I then published the MXD as a map service and imported my tiling scheme from my 2010 imagery.
Next I created tiles for the Full Extent of the service using Manage Map Server Cache Tiles dialog in ArcCatalog at my smaller scales (500K, 250K, and 125K).
I verified that the Area of Interest settings match the full extent as set in the MXD at time of publishing.
After creating the small scale tiles, I then used a polygon representing the boundary of our imagery for 1969 and set the Area of Interest in the Manage Map Server Cache Tiles dialog in ArcCatalog and cached the remaining scale levels.
The "missing" tiles now show up in areas that beyond the area covered by the 1969 at larger scales.
Mele