I have attached pics of a design I have completed. Unfortunately, the cost of machining such a complex design out of solid alloy as a one-off unit means I am unlikely to get it made. Anyway it was fun to design and nice to imagine how it might fly.
I wanted hatches that size so I could easily access the electronics and thruster wiring. I have designed the battery compartment as its own sealed unit so a battery can be changed without exposing the electronics to the air.
It has a payload of around 3 kg.