Load a file as eps (either an eps or an adobe illustrator file using the eps filter). Select the crop tool and crop it. The bounding box and the 'x' both disappear. Nor do they reappear if the graphic is re-cropped back to the original size.

The graphic is still selectable, but once it is unselected there is no indication of its presence.

Might be file specific, but importing EPS files and cropping worked here.

[Status updated to 'Works for Me' on Tue, 03 Mar 2009 22:10:43 -0500]