I have a 54cm Specialized Sequoia (my all weather road bike, and sometimes commuter) which due to it's "comfort" nature, uses a steep seat tube to bring the rider closer to the handlebars and consequently towards the bottom bracket. For long rides, my knees don't like that position so i used a set back seatpost to bring the geometry more in line with a typical road bike geometry. On a larger frame, I would have issues with standover clearance. I got my Easton post new along with a Fizik Pave seat ($70 on it's own) for $30 shipped off Ebay. I also picked up another FSA seatpost online for $15 during a closeout sale just in case I run into the same problem on another bike.