I am attaching a crop mark file I just made. It is a nominal 235 aperature, with a thirds grid. I am still futzing with it, as I am not sure if I have it aligned or sized right, but this file and the white in it, was generated using the original crop mark file provided with Magic Lantern. I edited it in Adobe Photoshop Elements, saving as an 8 bit bitmap file. According to Hudson, camera has to have that .bmp format.

The white area is transparent, under the set up. You can actually delete all the information I have on my version for instance, and make anything you want on it.
Hopefully other will post cropmark files here for our uses.

You can have multiple cropmarks on you CF card, but you will have to manually enter in the magiclantern.cfg config file, the name of the file you want to access as crop marks for your shoot, using a text editor, before you put the CF card in camera. A list access is planned for next version, according to Trammel Hudson.

here's my 16x9 cropmarks - for action and title safe.
. be sure to change the name as per the instructions.

reference links:
Adobe After Effects CS4 * Safe zones, grids, guides, and rulers (http://help.adobe.com/en_US/AfterEffects/9.0/WSA964B7EB-1AD1-489a-AEC1-2E8E92172D35.html)

http://www.motionworks.com.au/wp-content/blogimages/guides_lrg.png

Here is my take on the crop marks.

I used the presets in Photoshop to get the TV/Title safe markers.

Bright green lines, because.

I edited it in Adobe Photoshop Elements, saving as an 8 bit bitmap file. According to Hudson, camera has to have that .bmp format.
The reason for that restriction is that I wrote a very simple BMP parser for the firmware bmp_load() (http://bitbucket.org/hudson/magic-lantern/src/tip/bmp.c#cl-346) that only understands the simplest of formats. Canon's firmware has a full SVG parser (http://en.wikipedia.org/wiki/Scalable_Vector_Graphics), but I haven't figured out how to get it to draw my own vector images yet. Maybe the next version of Magic Lantern will have a better image loader based on jpeglib or libgd.

Hopefully other will post cropmark files here for our uses.
I've started a wiki page for collecting cropmark images (http://magiclantern.wikia.com/wiki/Cropmarks) as well. There you can see the sample palette of colors to choose from and some discussion of the BMP format.