5kg capacity
Lets say, we upgraded as a continent since then. Even though we have verry exagerated claims of capacity (up to 13kg in a standard EU\compact US form factor), we do have washers with 70l/2.5cuft drums, thus a realistic load capacity of 7-8kg over the common 50l 10-15 years ago.
However, I don't quite see why a H-axis machine would be limited in capacity. Taking of the top of a usual FL reveals there is mostly only 1-2 inches between the top lid and the outer drum. Just move the opening like on the EU TL H-axis machines, use a simmilar rubber seal as these designs and basicly keep everything else. Then buy the Fisher&Paykel TL dryer patents, redesign it so it hits the safety standards again, and boom, you've most likely got a significant market share.
And then, do it like GE with their RightHeight FLs and make them higher, and use the additional space for a heatpump drying unit. And boom again, highly efficent, well usable washer-dryer combo that could dry reasonably well on a 120V supply.