Highlight to quote is already there in Burrow, it also works from the integrated browser if you'd like to quote from a webpage.

I'll add anything that is missing in a few days

Would appreciate some testing of these 2 features if you use studio

Browse the thicket from the reader. Every quoted layer in an entry, at any depth, now says whose it is and opens in the reader

from Blygger ↗ · excerpt of v1

A stub's passage is selected in the editor's own preview. The separate chooser pane

from Blygger ↗ · excerpt of v1

from Venkatesh Rao's Blyg ↗ · snapshot of v1

neat! I've been hoping for something like this. I had text highlighted when I hit stub and it didn't quote it like I expected though.

from Kyle's blyg ↗ · snapshot of v1