http://www.gettyimages.co.uk/detail/...mage/556482507
Like this but more diffuse and slightly wider; paint it in on a separate layer then use a mask to hide everyone else and change the opacity of the layer until it looks natural. You can paint over the top of the mask with a low opacity brush (like 5%) to hide or bring out more detail.
http://www.gettyimages.co.uk/detail/...aphy/157043675
The key to the suitcase is darkness immediate on the bottom and underneath, then rapidly getting lighter. It needs to be small but define the light.