Son of the BOCPAG game, slightly different rules.
Post a frame you don't want. Hope someone posts one you do want. Two-way trades, three-way trades, fifteen-way trades, whatever you want. But all parties should agree to all stages of the trade before sending anything.
My submission: 1994? Bianchi Eros. Made in Japan. Lugged frame with Ishiwatta something-or-other tubing. Unicrown fork. Needs paint. Vertical dropouts, so no good in case you want a fixie. 55 cm seat tube. 56 cm top tube.
it's not usually an issue, but we should probably be really careful in this to define whether seat tube length is center to center, center to top of top tube, or center to top of seat tube. Actually, even if your frame is "sized" based on center to top of seat tube, like the vintage Masis are, it probably shouldn't be quoted, since it's hard to tell from this if the frame will fit.