For the anime Ro-Kyu-Bu, which will come out later this year, a new singing group of seiyuus has formed: Hanazawa Kana, Hikasa Youko, Iguchi Yuka, Ogura Yui, and Hidaka Rina.
Hikasa Youko is the only one of those whom I know to be a good singer, but their look may make up for any other weaknesses:
Ro-Kyu-Bu is a series of light novels that started in 2009 and won Dengeki's novel award. The story is about a high-school boy (Kaji Yuuki) who becomes the coach of an elementary-school girls' basketball club.
To give you an idea of what the show may look like, here is the cover of the second novel:
The same five seiyuus will be in the Drama CD, which comes out next month, and in the anime, which is slated for sometime later this year. Itou Shizuka plays a teacher.
Ogura Yui (15) is an idol whose movements were digitized for Hatsune Miku's dancing in Project Diva. She has been in several TV dramas, and is beginning a career as a seiyuu, having been Ringo and Mint in Yumeiro Patissiere.
Hidaka Rina (16) is an actress in TV dramas who has become a seiyuu, most notably as Last Order in Index.
Hikasa Youko is Mio in K-On. Iguchi Yuka is Index in Index. Hanazawa Kana is Nessa in Fractale, and was Tsukimi in Kuragehime, etc., etc.