* Nikkei down 1 pct, eases from 7-mth high * Elpida untraded with glut of sell orders * Chipmakers down on Elpida bankruptcy filing * Shippers, banks fall By Mari Saito TOKYO, Feb 28 (Reuters) - Japan's Nikkei average retreated from a seven-month high on Tuesday as participants took profits ahead of a key selling level at 9,700, while Elpida Memory Inc was untraded with a glut of sell orders after seeking bankruptcy protection. Elpida, Japan's last remaining maker of P