Idea for kitchen peninsula
The problem with using upper cabinets on the floor will be the lack of a toe kick. While you may not NEED the functionality of a toe kick, you can't have the cabinet door right next to the floor. You will need to build some kind of base for the cabinets to sit on.
OR you could stack cabinets. Maybe regular lowers with a second row of cabinets on top. Since you have limited depth, maybe, as LawnGuyLandSparky suggested, base cabinets with doors on both sides and then a row of uppers placed on half of the lowers. I guess it really depends on the depth of what will fit.