I found a picture which might give you some ideas. You have to use your imagination. Lol!!! So, use the stone you like on the columns and your travertine for the seat of the bench and the caps of the columns. That's almost what ya'll were first thinking about, but without using the stone on the middle sections between the columns. I can't tell what was used in this picture for the back or the bench or under the bench. Maybe AmyJo, Kim, or someone can tell.
If the picture doesn't work right (I can't tell in the preview), it's because I'm totally lost without PhotoBucket. It took me an hour to get the picture this far.
In the picture, imagine the columns square and taller, the back of the bench taller, and the entire thing not as long. And get rid of the firepit. That's all....Lol!! Then you've got yours!
Mama Suz