I ride a 54 cannondale with a decent amount of drop but recently flipped the stem up to get a less aggressive (read less painful for my back) position.

The trek is 56 and I need maybe half an inch to an inch more of seatpost. The seatpost is stock from what I know, but I really like the silver fluted seatpost. Anyone know where I can get one for the frame? I don't know what diameter of post I need. Does anyone have one of these bikes and know?

I might swing for a modern silver post if the diameter is the same.

Thanks.

P.S. Lets not start the frame sizing debate. I like my bikes the way they are.