Does anyone know if anyone has created shadowmourne yet?
Is it still too early? I'm surprised I have not heard much about this.
Note: The following text was written before the first Shadowmourne was created on 2010-03-17, by Modk, of Juggernaut on US-Mal'ganis.
Based on some research I did last week, with the bits you need to collect, the earliest that someone could create a Shadowmourne, practically speaking, is in April, with very good drop chances. Essentially, each boss on 25-man ICC gives you a 33%/75% chance (normal/heroic) of getting one Shadowfrost Shard, and you need 50 of them. Unlike TOC, you can't do bosses on both hard mode and normal mode, so the best you could do would be clearing Hard mode ICC 25 every week, and getting 8 on average -- the soonest you could get it would be 6-7 weeks after the quest. (Of course, it's pretty much impossible to get the actual drop rates; these are based on the 25-50 range for normal and 50-100 range for hard on the Armory. Wowhead lists drops, but they're based on people who have the quest, so impossible to tell what's actually happening there.)
So, assuming a middle-of-the-road average for bosses, the soonest you would expect if you were clearing every boss on hard mode every week is 6-7 weeks after you started the quest, which wasn't possible until the final wing of ICC was released. The fourth wing opened on February 2nd; this means that with a perfect drop rate, and completing the quest the first week it came out, we're probably just passing the time when you could expect one to be created. I expect we are likely to see one in the next 2-4 weeks.
So, yes, that's why you haven't been hearing about it yet, as the first one just came into existence on the live servers on March 17, 2010.
Picture taken from MMO-Champion: