The places I've been looking at have been:
Monthly Chintai -
http://www.monthlychintai.com
Leopalace 21 -
http://www.leopalace21.com
Sakura House (already linked to)
PAL -
http://www.fudosan.yoursnet.com
Wave -
http://www.eg-wave.com
How far are the Shinigawa and Hamamatsucho area B-sites from TUJ, if you don't mind me asking? I mean, the main areas I've been looking in have been Azabu Juuban, Roppongi, Higashi Azabu.