Search for "Frost Protected Shallow Foundation". The issue with loading is not depth but stability. Stability from settling and stability from frost heave. conventional foundations are designed to address both - depth for frost protection footing size and placement on deep undisturbed soil for settling.
A FPSF can be designed to address both problems using less material and excavation and are common in many (cold) parts of the world. The do required careful attention to detail and are not what most contractor are used to...so you will have to step in to make it happen. With proper insulation, compaction and edge design, you can accomplish your goal. The thickened edge on a FPSF has as much or more bearing area than a conventional deep footing. You don't get the easy undisturbed soil or insulation that is inherent in a deep foundation is all...
I am not talking about frost protection or frost heaving.
I am talking about the differential load on a load bearing wall, with a 2nd floor and probably some serious snow loads in MI and the attached slab which basically has zero load on it.
That load puts the concrete slab surface in tension and right at the mono footing edge and slab you get a crack because concrete has very little tension capacity and the rebar is not engaged in tension until you do have a crack.
This is compounded by the soil or base under a shallow footing being subject to ever changing moisture content.
Having a conventional footing with a floating slab, no forces are transferred from the footing to the much thinner and structurally weaker slab.
Of course any footing has to be wide enough for the loads and on stable soil or fill.
