I've seen a tv show where there was a basement similar to this, with the foundation that was thicker on the lower half. What they did was made the wall a consistent thickness on the bottom, then did a ledge all around the room with the top half regular thickness walls. The ledge was kinda nice because you could make it a long running bookshelf, use it prop art, place your treasures...etc. I would consider doing the same, making the ledge at a good consistent height all around the room for use in your office.

clever! thank you

maybe it won't be so bad with stuff in it.. at least until i figure out how to make a ledge

Hi Diane, this living room has a ledge that might work in your situation. You could even consider some open shelving that will cover the exposed foundation.