Someone posted in web/db that they easily moved Karl's stuff to Solid, so perhaps moving it to Postgres won't be difficult.
It would be nice to have it up so we can play with it and get some experience with it. Hint hint :)
It would be nicer to find out what aD plans to do in this area long-term. I've not dug around in a few weeks, but last time I did it appeared that they've not settled on a single approach.