http://www.bikeradar.com/road/gear/article/best-soft-riding-rigid-seatposts-for-road-dirt-and-gravel-46208/
So the original VLCS or Ritchey Flexlogic looks good.
@gillies started
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http://www.bikeradar.com/road/gear/article/best-soft-riding-rigid-seatposts-for-road-dirt-and-gravel-46208/