I'm not sure if this is technically possible, but here's an idea. I'm trying to have the images on my site cross-referenced as much as possible to invite people to browse MORE. Obviously. :)
Most recently I switched to Jetpack's "Carousel" image viewer because it is one of the few viewers that shows the image title, caption AND long description.
The attachment pages on the other hand have received extra love with WP3.5 and are almost like a full post now, and from my point of view, the long description would be an excellent place to add references to the galleries/portfolio items (whatever) where the images are used.
I was thinking of something like [mla_where_used] which would then output a (configurable, freely formattable) string like "This attachment appears in <post title1>, <post title2>, <post title3>", where <post title1> etc. are links of course that the visitor can click on. :-)
Or maybe something like [mla_where_used id="1234"] to show where one specific attachment is used, so that it can be used not just in attachment pages, but posts, pages etc.
Another benefit would be that users can find "back" into the site in case they ended up on an attachment page through a Google search, or some other way.
Alternatively, this could perhaps also be something for a widget that could be placed into the sidebar of an attachment page?
What do you think?