1. Steam powered "espresso" isn't. It just can't get up to enough pressure. If you want espresso, steam power is out.
2. the Mypressi Twist uses CO2 cartridges for pressure. It wouldn't take long to brew two doubles. (just two rounds of brewing, each at 1min. or less)
3. So, warm the milk first. Alternatively, you could use a French press to aerate the milk if you don't mind intense washing between milk and coffee uses.
4. There is no such thing as stove-top "espresso". There is stove-top pressurized brewing, but it doesn't come close to approaching 130psi. At this point, if I wanted a lot of volume in little time, concentrated, and brewed under pressure, I would just stick with an Aeropress.
Didnt steam powered espresso predate piston, actually? It seems like we've redefined espresso and then rewrote history. Not to say it's better, but steam is original.