I have just made the questionable choice to purchase a second X11DPL, and this time I don't really want to spend $200 on a pair of Noctua tower coolers. I will likely end up with Dynatron B13s or the coolers from the HP Z6 G4, but before I commit I wanted to see if anyone knew of a better (which is to say taller) option from Dell, Lenovo, or whomever. Passive is fine, I can design and print fan ducts, and in case it makes a difference, my initial plan is to use 85W CPUs.