In a lot I purchased from the 'Bay recently, I found this little enigma. I'll try to post some pics later.
It's a vest-sized pen - not a ringtop. The clip and cap end are all of one piece, chrome plated, as are the cap band, filler lever and lever box. In addition, the cap band, filler lever and lever box have a raised checkerboard or diamond pattern. The lever is segmented, and does not have the "Ideal" logo on it.
The nib reads “WATERMAN’S IDEAL REG. U.S. PAT. OFF. 2." The barrel and cap are green striated. Discolored once-translucent plastic covers approximately half the barrel, with a green checkerboard underlayment. The imprint reads “WATERMANS IDEAL, REG. U.S. PAT. OFF., MADE IN THE UNITED STATES OF AMERICA." The "Waterman's" name is in a later outline-style font.
Any guesses what I found?