The TR 13' 7 weight would make a great starting point for Echo CP's to evolve from.
Be a nice touch if they'd utilize the TR spey handle, just reverse the longer fore cork to bottom/shorter rear cork to top, and just stick with the same reel seat. (DH style corks on the TR CP build would be even better.)
They get this as right as their factory speys at similar price and they'll have a definite winner.

Keep us posted.