From Cacidi Systems:
Cropmarks 3.0 applies cropmarks, bleedmarks and guides to individual objects in your Adobe InDesign document. Customize your settings: Easily set your own preferences for length, size and stroke weight in crop- and bleed marks. Cropmarks: Define length of cropmarks, space between object and cropmark, and even stroke weight.
Bleed marks: Add bleed marks to individual objects, and check in layout mode if sufficient bleed is applied. Bleed works independently of cropmarks, but is always automatically applied beyond cropmark setting point. Guides: Automatic guide to each object feature.