I'm interested in this too. I found this: http://gaming.stackexchange.com/questions/28438/is-there-a-way-to-increase-the-number-of-items-displayed-in-the-kill-feed
However I'm unsure if it's required to pull the original hudlayout.res from TF2 or if I can just create a new one with just the HudDeathNotice block.