I'm tempted to do just this, but I don't really need the extra capacity just yet. I might wait for a few people to perfect the technique. I hope there's going to be a write-up of the different attempts on the remarkable wiki [1]
Since the remarkable has a micro USB port, does anyone know if it supports OTG devices?
It's such an awesome device. 90% of its awesomeness comes from the fact that they respect the GPLv3 license and give you root access to it trough ssh out-of-the-box (random password and requires activating it).
If I get enough time on my hands, I'm probably going to port postmarketOS on it.