This is the lastest profile I am considering for the linear rail. The configuration allows it to be compatible with the current wheels and brackets by maintaining the same v distance. This will allow people to mix in steel and hardened steel as required.
The V center is parallel with the extrusion edge which is a little different than the 2.x, but 2.x is designed to adjust in this direction. I did that to improve the stiffness.
The V rail feature no longer extends onto the 40mm side. This will allow 40mm extrusions to be attached (butted) to the side. The 2.x requires this and it adds more flexibility to it's use.
I was tempted to add slots to the front surface, but decided the extra stiffness to the load (compression) of the wheels was more desireable. There is a center mark which will simplify drilling and tapping if a bracket needs to be mounted to that surface.
The width of the v still allows a standard bracket to be mounted to the 20mm sides as shown in the rendering.
With this extrusion, you are now free from reliance on Misumi. Any 20mm based extrusion can be used to build the rest of the frame. Even inch based systems or other materials could be used.