Doug, thanks for the reply.
Yes, I know overviews and caches are different. Since caches are using overviews as their sources at higher levels, then I was wondering if there was an existing overview scheme that closely aligned with the tile schemes such that you could cut down on image degradation due to reprocessing.
The lower levels of the ArcGIS/Bing/Google tile schema (e.g. 13-19) may use the original data via the mosaic dataset, but the upper level, e.g 7 through 12, would be better to draw from pre-computed overviews. So i was thinking it would make sense to have the overviews computed at those levels.
It's probably more of an academic question than a practical one.
Thanks
George