interesting idea!
I have a batch of small glass bowls - when I need "perfect" poached eggs I put them in the (cold) water - depth to generously cover - and bring the water to a fast simmer.
crack the egg over / into the bowl - it sinks into the bowl and sets up perfectly.
tip: wipe the bowl inside with a little vegetable oil prior to heating; eggs edges like to stick to the too-clean glass . . .