A pink rectangle, painted on the white wall, defines the loft's dining area, above, and serves as a backdrop for the portraits, by John Woodrow Kelly, ofJayne (right) and Rick Ellis (top).   An ocher-colored block frames the bed ,(top right), a family heirloom. Anidentical ocher block frames a chest of drawers on the opposite wall. Jaynebought the oval mirror at Pottery Barn and painted it coral.   Far right: Acid green blocks delineate one end of the dining area, (bottom right), and a wall of the living area, (bottom left). Sconces by the English designer BelindaEade flank a pink nude by Van Jensen, which Jayne and Ellis bought in theEast Village. Theshield-back chairs, on either side of the antique American drop-leaf table, are 18th-century; their faux-tortoise finish came later.