Looking for a band or artist similar to Mr. Children...

any suggestions?

ﾆ築ﾂ゜ﾆ脱ﾆ停?愴置

Similar?
Hmm, how 'bout trying Kobukuro or Surface?
Here's some link to YouTube for your trial:

-Kobukuro - Kimi to iu Na no Tsubasa (PV)

-SURFACE - Re: Start (Sorry, I couldn't find PV for this song. Please bear with this subbed anime video)

Surface's official website is here, and you can test-listen recent album/single under "sound/video list". Make sure you click the blue one to listen to them for free, as red one with Yen mark is to download the full size version(you have to pay).

These are just one of their various songs, so even though you may or may not like them, you could always try thier other songs!

Also, though I'm not into this, Tsuyoshi Domoto(One of the guys from Kinki Kids) has a VERY similar way of singing(and voice) to Mr. Children, as he's a fan of them himself.
Machi
Someiyoshino

Hope you like it.

Cue

Oh, I came up with another band similar to Mr. Children, Aqua Timez, that is.
They say their music has been influenced by Mr. Children themselves.

Here's some of their videos on YouTube.
-Ketsui no Asa ni (Theme song for the Movie "Brave Story")

-Sen no Yoru wo Koete (No video, music only. Theme song for anime "Bleach The Movie")

....I am starting to wonder if Oonter still visit here, though. ;