http://www.agoptical.com/idk/default.html
They have 12.5, 14.5 etc. The 12.5 inch is a truss which would have to be an advantage against tube thermal currents. Also quartz mirrors and rotating focuser included in the price which I believe is less than Planewave or at least it used to be.
Orion Optics is closed tube so keep that in mind. More prone to wind and thermal currents. Ages ago they had an issue with their corrector. I presume that is now fixed but worth checking on.
Greg.