Yes, I will send a sketch, hopefully tomorrow.
It would require single mounting plate that bolts to the rear of the OTA, as per normal, and is long enough to mount the NEAF clear of the edge of the OTA with the shaft facing to the rear, parallel to the OTA and OTA focus shaft.
There would be a small timing belt wheel (pulley) on the OTA focus shaft and a larger one on the NEAF shaft. The aim would be to increase both the rotational speed and travel distance by 4x. This would also increase resistance torque 4x, so that would need to evaluated.
An important consideration would be the smallest wheel (pulley) that can be fitted to the OTA focus shaft, given that it has the larger diameter. If it was a 15 tooth pulley then the NEAF would ideally have a 60 tooth pulley.
If the torque considerations and physical size of the two timing pulleys are feasible, I think that this would provide speed and travel characteristics better suited focusing by means of moving the primary mirror. It would also eliminate back-end clearance issues for Alt/Az mounts.
EDIT: If the timing belt & pulleys proves impractical, another option could be nylon gears.