In the past, it was possible to export or print from InDesign with a set of crop marks that were not the default. Full details are available from http://indesignsecrets.com/creating-custom-printer-marks-in-indesign.php
However, it has been some time since this post was written, and when re-visiting the situation to see if it would help other posters trying to make their crop-marks black only, I have not been able to make the marks in CS6 on a mac.
If it works properly, this highlighted checkbox changes from "default" to something else.
Image may be NSFW.
Clik here to view.
As it stands for me, it will not change beyond "Default" to the point where it is literally there as a decoration.
Has anyone else tried to change their cropmarks since CS6 and if so, how did you do it?