You're so awesome! Thank you ! After I posted I was like, maybe they're sewing machine legs! And that's what the RH description says! I will use this as inspiration! I actually have a singer sewing machine base and an old wash tub I am making a laundry sink out of so something like this will go with my other diy pieces!

If you use the leveling legs, you will almost certainly need more than 5 for a 70" cabinet. Don't skimp or your cabinets will sag. I have used leveling legs for 3 cabinets installations and love them. They are quite easy, even for long cabinets and runs of multiple cabinets. The instructions for the legs that I use say that for European-style cabinets (i.e., frameless), the legs must be mounted directly below the bearing uprights (sides and any intermediate uprights, as it sounds like you will have in the center of the 70" cabinet). In two separate applications, I installed a single frameless cabinet ~70" wide in each of two yurts, both with uneven floors. Each of those cabinets is divided into 3 equal sections: drawers in the center and a single drawer/door combo on the two sides. I used 8 levelers: 1 pair on each side (mounted as close to the edge as possible to support the vertical sides), and 1 pair directly beneath each of the two dividers. The levelers worked like a dream. I also used leveling legs on my own kitchen cabinets, though these are face-frame construction. I have 33" wide drawers, and the deepest ones (14" inches) hold my cast iron so they required adding 1"x3" struts front-to-back beneath the drawer bottoms. So what you should do? If you choose to use leveling legs, use 8 legs in one of two configurations. In the first configuration, change the 70" cabinet configuration to 3 sections rather than 2. Then you would mount one pair of legs on either end and two pairs beneath each of the section dividers (uprights). The second option would be to stick with you single upright divider, and mount two pairs on the ends and one pair under the upright divider, plus 1 leg centered in between each "pair of pairs" - hope that makes sense. If you choose the latter option, I would recommend adding reinforcement to the cabinet bottom to distribute the load borne by the 2 "centered" legs (e.g., a 1"x3" strut side-to-side, or simply a double-layer cabinet bottom that doesn't need to extend so far forward as to be visible). Good luck and please post your results! ETA: I just looked at a photo of one of the yurt cabinets, and it actually has 12 legs: 4 under each section of 3 sections of the 70" cabinet.

Beautiful base. I don't have a magic formula, but I think oval is a better choice, less likely to hurt a person or be damaged if there are no corners to bump. The more overhang you have, the more risk of the top tipping. Perhaps try mocking it up by using painters tape on the rug or cutting a disposable plastic table cloth to size?

We also build custom doors for IKEA. We add open boxes or shelf units all the time. They are just built out of the same materials as the doors or could be a contrasting material like wood veneer.