The simplest answer is indeed that the kind of product you want does not exist yet. But perhaps
ONYX BOOX T76ML Carta comes closest. It has the same screen as Kobo H2O and the Android can be officially upgraded to 4.4 from what I have heard.
I have Pocketbook Inkpad 2, 8" screen at about 250 ppi. It has inbuilt Dropbox, RSS reader (I use those), Readrate (I turn this one off), and very good notetaking-bookmarking-highlighting with the inbuilt reader app.