In honour of his upcoming Yahrtzeit - (first day of Rosh HaShanah)
Go to HaLevanon and search for שנת היובל. It's an article (written in very heavy Melitzah) describing describing his difficulties as Chief Rabbi of Bucharest (he was thrown into jail and only released thanks to the efforts of Moses Monetefiore).
See Heichel HaBesht for an article on his relationship with the Chassidim. The standard work on Malbim is Noah H Rosenbloom, "Malbim: Exegesis, Philosophy, Science and Mysticism in the Writings of Rabbi Meir Lebush Malbim ( In Hebrew)". See Sefer Hamalbim - A. Surasky (on Otzar Hachcoma) for hagiography and some minor works of Malbim (commentary on Rambam Deot Re:Health and Poem). More recently, see Yaakov Heller, "New Documents on the Malbim Affair and his Struggle with the Maskilim," The History of the Jews in Romania: The Nineteenth Century (Tel Aviv, 2005), 2:231-258 (M. Butler told me of this source - I don't have it).