Originally Posted by 79pmooney

But ... Thompson clamp parts can be purchased from Thompson so a framebuilder with skills could make you a custom post of any setback using Thompson hardware. I have two TiCycles posts with aluminum heads and titanium posts, each with roughly 60 mm setback. Wonderful posts. (My preferred bike, no holds barred, has a tight rear end, 74 or steeper seattube (to accommodate the close rear wheel with decent size tires and fender. I want a setup that puts the clamp midway on my favorite seats so lots of options are available in the future. So I could go either curved seattube or big setback post. Maybe one day I'll spring for that curved tube.)

So, you have the option of ordering a TiCycles post of any setback you want with that first-class hardware. And being completely custom, everything, post length, material and diameter, finish, etc, are on the table. 2011 prices were ~$160 for mine. Their prices have gone up but not radically.

Edit: I hadn't read veganbike's post above yet when I wrote this, but I submit it now as an example that his generality isn't always true.

Ben