Okie-doke... here's a nebulous but maybe encouraging idea...
Up until now, my primary interest in mods to the ToD system has been to achieve a true 4WD-high mode (50%-50% lockup in high range) for short-of-treacherous winter driving. But with the current price of gas and the potential for a substantial improvement in mileage if the front axle could be uncoupled at the transfer case and installation of unlocking hubs, my interest in modding the ToD is expanding...
So - earlier this year, I had a problem with my ToD system - some of the wires running along the underside of the VX had come loose and were resting on the cat convertor. This naturally melted their insulation and shorted them out. The short blew out the ToD fuse, and I got the "check" light on the ToD display. At that point, I think the VX was running in rear-wheel-only (2WD-high) mode because it seemed that only the rears were working on our snow-covered ski house driveway in VT (I was able to engage 4WD-low to get full lock-up, even with the ToD off). Of course, this observation would have to be verified by putting the VX on jack stands, pulling the ToD fuse, and putting it in gear to see if the fronts turn at all when the ToD is de-powered.
But if it's true, here's the potential mod to get just true 2WD-high mode: a simply switch in the wire that supplies power to the ToD (or it's ground - automotive electricians, please advise) providing the necessary decoupling, if you don't mind a "check" light on the ToD display (I sure wouldn't!).
If we could do that with a selectable torque split which includes full-decoupling, that would of course be the best solution.