Can you include some photos of the space? Also, what is the height of the ceiling?

Concrete ceilings ... so I'm guessing recessed lighting is not an option?

Here is how this ceiling looks like....

It would be difficult to install overhead lights, so I suggest a high-wattage halogen indirect floor lamp with a dimmer that will direct the light to the ceiling and provide good illumination in the space. Another option is an arc lamp for the main seating area and maybe additional table lamps, depending on your furniture layout.

This is really rough, but should be good enough to give you an idea. Put up some shallow fake beams in strategic places to hide the rougher parts of the ceiling. This will also allow you to put lighting in the crosses. Also, you won't loose any real ceiling height.