Looks like Mauku will do what I need, then.

I have tweetdeck open right now: it shows a timeline of all my friends and my tweets, any replies to me even if they're not from my listed friends, a search I follow on one of the 'celebs' I interact with so we can have group conversations, a search on a hashtag and my direct messages. I can tweet, reply or direct message. I can also retweet. If retweet is missing, you use reply (to get the name) and copy/paste for the content (Maemo does that!) and shove RT in the front, so its absence isn't citical. Unless I'm mistaken, Mauku will do everything that tweetdeck does. And a whole pile more than jtwitter. Good enough for me!