There are so much shoujo manga that I love reading and I definitely wanted to be adapted into Anime and/or Live Action. But so far, I can only think of one which I already have prospective appropriate actors to play. That is: Love So Life by Kouchi Kaede!

Honoka Miki (Itazura na Kiss Love in Tokyo) as Shiharu Nakamura (right)
Tamaki Hiroshi (Nodame Cantabile) as Sieji Matsunaga (left)

Aren't they cute?

^__^

[Scantalation from Mangareader.net]
[Actors photos from Asianwiki.com]