Yes, gave the HD-800 away. I know that the better the amp the better they sound, but they had other limitations besides amping.
Yes, the 1440 sounds more like the HD-800 all the way around, top to bottom. And based on prior user input from the SRH-940, I would guess that with the best amp you can pair with the HD-800, if you use that same amp with the SRH-1440 you will also get very close to the HD-800's sound. Or you could save a ton of money and buy a 1440, a small amp like the O2, and just get some foam or cloth inserts for the earcups to dampen some of the excess highs, and have 99.5 percent of perfection for 10 percent of the cost. Or just get the 1840 and skip the rest.
I tend to think of the Shures (esp. the 1440 and 1840) and the Grados (esp. the PS500) as archetypes for the "cool, neutral" and "warm, lush" type of sound. I am not familiar with other major brands like AKG, Audio-Technica, Denon and perhaps a couple others to see how they would fit into those archetypes. I am familiar with Sennheisers, but I think they're somewhere in between.