Yes, of course! I mention Ivan Ilyich in my article "All's Well That Ends Well: a Few Words about the Optimism of Pushkin, Tolstoy, Mayakovskiy, Pasternak and Nabokov" available (in Russian) in Topos: http://topos.ru/articles/0907/03_04.shtml. Also, I speak of Ivan Ilyich in "Van Veen or Ivan Golovin: What is the Real Name of Ada's Protagonist?" (don't remember where/if it was published). I believe I also mentioned Tolstoy's hero in Nabokv-l. One soon forgets one's own words if nobody responds to them.