50 KB in size, easily fits in any Java ME (J2ME) phone (CLDC 1.0 and MIDP 1.0 minimum), and still loaded with handy features like quick reply, url-friendly smart retweet, custom/auto word list for quick insertion (like @having or #gaza), and able to open url in a tweet directly. Another plus, small bandwidth consumption, via birdnest proxy (5-6 KB for 20-entries timeline).
#jibjib - Java ME Twitter client - http://jibjib.org/
*jibjib (จิ๊บจิ๊บ) - Thai for “tweet”, also means “small, easy matters”, and the best of all, it starts with ‘j’ ... hey, it's Java application, don't you forget? :p