Tokyo Tsukemen Fest 2013 (東京大つけ麺博 2013)
I just looked at the website and the two top shops- Tomita and Otodo- are in Matsudo. Ugh, a bit of schlep from most parts of Tokyo.
The event actually has a nicely done English page- http://dai-tsukemen-haku.com/en . I was slightly surprised to see that Shina-sobaya took part. This shop, which has been at the ramen museum for a while, is run by the guy we used to call the "ramen nazi" a la Seinfeld. I wrote up an account years ago- http://chowhound.chow.com/topics/324870 ....Anyway, the pictures of the entries for the entire event look positively delicious.