I'm still a bit heartbroken...
but that doesn't stop me from fantasizing a dream Ouran LA cast!
My nominations for cast are:
Haruhi:

Inoue Mao (Hana Yori Dango 1 + 2)
Tamaki:
TBD, but he has to be insanely cute and tall.
Kyoya:

Oguri Shun (Densha Otoko, Hana Yori Dango 1 + 2, Stand Up!!, Detective Conan SP, and a whole bunch of other dramas)
Hikaru/Kaoru:
Okay -- let's reject the idea of getting actual twins. Face it, there aren't any pretty pretty twins in the Japanese Entertainment industry.
With the power of editing technology, we can just get ONE pretty boy to do double-duty!
Which one?
TBD.
Mori:
I'm very tempted to nominate Hayami Mokomichi (Gokusen 2, Brother Beat, Regatta, Densha Otoko) because of the height and toughness, but I can't exactly imagine him as quiet.

Hunny:

Nakajima Yuto ... wait, HE GREW TALLER! He's now taller than me! 154cm T_T . That's like, 6 cm off! Well, the Hunny flowers look well on him!
Okay, we'll stick in one of the Johnny Juniors!
Renge:
TBD
Nekozawa:
TBD
Lobelia Girls (maybe do without them?):
TBD
Ranka:

Kaba-chan (Gachibaka!)