Yes, it can be done. Just put your main video on the Video 2 track and then put your decorative graphics "behind" (below) it on Video 1.
Although most people find it's less distracting to just left the sides black. Adding graphics to each side just draws more attention to them.
Now why didn't I think of that? How simple!
Lee in Ohio
YouTube uses a 16:9 player. So, the following guidelines for these uploads and a black bar issue may be of interest
Please see section Resolution and Aspect Ratio in the link above.