"Hey guys, let's photograph this chair in a dual solar system!"
This is why you have rendering software. ;)
Actually, there are even more common situations, I have seen quite a few photos with two suns already. For example house, which is from one side lit directly by sun, and from other side, there is a huge glass building, which reflects sunlight back on the house from other side, creating only slightly less intense and slightly more blurry light. There is a lot of reflective surfaces outside, so spaces can often be lit in very interesting manner. :)
Or at evening, when there is a dark blue light coming inside from window, you can be in an apartment that is on some of higher floors, and there can be actually street lamps shining into your room from bottom on the ceiling. That is also quite interesting lighting situation i have not seen anyone to use.