@shel @maiyannah @stitchxd @KitRedgrave
#Hubzilla actually has a fairly flexible system for templating, though it requires some familiarity with the system's conventions to write your own unique widgets from scratch.
Still, in theory you could write a Tweetdeck-like UI for it; the question is whether you would actually want to, given that the platform lends itself to long-form content.