I've got a set of used 170 mm captain cranks available. They are Shimano 105-level, probably about 15 years old, but I bought them as new-old-stock last year, so they've had very little use. Model number is FC 1057. They are about the 10th item shown on this page, with photos (I've got several other bike parts that I'm selling that are all listed on that page). Price is 60 Swiss Francs (63 USD) for the cranks, and 20 francs more for the bottom bracket. Shipping to N. America from Switzerland would be about 30 USD.