We looked at that option even calling Borg Warner about making manual locking hubs. Borg Warner said no reason to develop a manual locking hub, their system works as designed.
If the IWE was on the outside of hub it would be easy to make a manual lock. Since it is on the back side of wheel bearing there is no way to access the stupid locking ring from the front.
I went as far as getting a f250 hub with manual locking hub and trying to figure a way adapt it to f150 spindle/upright and axle.
Going to talk to RCV about changing out the outer part of the axle to a fully splined outer axle. If this is possible, then might be able to make it manual locking hubs with already available off the shelf products.
Something like this.
-Greg (aka Squatting Dog)