Simply target a ship and the cargo space used is displayed, then use the 'n' key to display the contents of the hold:


I did a fair amount of testing and it seems to be about 99.9% accurate, I did pick up a pod that had something that was not listed, but only once. The numbers for gold, platinum and gems are not always correct but sometimes there will be two pods containing these commodities so there is often more than the scanner listed. I guess some commanders are able to stash some of these commodities without adding the numbers to their manifest.
I'd like to add some more effects like a delay timer and maybe an energy drain, but I am no coder and I may never get around to it. It might also be interesting to add some AI effects, right now npcs don't respond to it in any way. I haven't got a lot of time for this right now but I wanted to get it out to the community. If anyone else is interested in adapting this have at it

I have restricted it from 'safer' systems so you will only find it in anarchy-dictatorships.
Get it here:
http://wiki.alioth.net/img_auth.php/8/8 ... _1.3.2.oxz
Many thanks to spara for the original manifest mfd code.
edit: updated link