Third party ethercat motion controllers

We are looking for recommendations for 3rd party EtherCAT motion controllers to integrate with a cRIO system.  I am aware of this article.  We will be driving 5 rotary brushless motors (moving them a couple of "steps" movements at 400 Hz).  They have high resolution encoders (something like 1.2m positions per revolution).

We have spoken to Beckhoff but they don't support the high resolution of our encoders.

Any recommendations would be greatly appreciated.

Steve