[JohnnyCanuck]

I want to build up a 2009 SE vertex as a single speed but I don't want to use a chain tightener. Anyone know of any after market horizontal dropout that would work?

 

[rockyuphill]

The problem would be that you couldn't retrofit the frame with new dropouts without having the frame heat treated again, so that pretty much kills your SE paint.

How about searching for magic gear ratios? Here's a calculator to find the ratios that might work without a tensioner.

http://eehouse.org/fixin/formfmu.php

Or an EBB that can fit a standard BB shell

http://forwardcomponents.blogspot.com/

Or a White Eccentric rear hub

http://www.whiteind.com/rearhubs/singlespeedhubs.html