I'm also interested in this concept because I like the functionality of the 2 way rods and the ease of installation (no specialty curved jigs). MLED you're right in that every 1 piece neck build I've seen uses the traditional curved rod. Also, in looking at telecasters from various years and setups, some have the adjustment at the headstock and some at the heel. I did a quick calculation on using a 2 way rod on a one piece, rear mounted neck that I'll share.
You might be stuck with only being able to have the adjustment at the heel, because I think you'd be too low for the headstock because your trussrod channel starts from the rear of the neck. This isn't a problem for the traditional rod because it arcs up at each end, you just drill the hole in the headstock to meet the rod channel.
The stewmac 2 way hot rods are 11.1mm deep. I added another 4mm to the trussrod channel you would need to route as space for the 'skunk stripe', totalling 15.1mm deep channel. A random telecaster spec I found online states a thickness at the 1st fret (thinnest point) of 21.8mm.
21.8mm-15.1mm = 6.7mm of material from the fretboard down to the channel. Which seems like it would be enough material to be strong enough.
One question I have about the 2 way rods is whether they can be installed with the adjustment nut on top or bottom. The pics on stewmacs website has them all on the bottom (meaning the back of the neck) .
It does get slightly more complicated. The skunk stripe/trussrod channel on traditional truss rod fenders doesn't go all the way to the end of the heel. It stops before the end and a hole is drilled from the heel to meet the channel (just like the headstock end) and the rod is fed through. Because the 2 way rod is thicker, one would have to make the channel and stripe slightly longer. I was considering using a spoke nut rod so it could be adjusted without removing the neck, which seems tedious. But because the spoke has a larger diameter than the rod it is attached to, I would have no choice but to route all way to the heel. Then, like some fenders that have this rod type, route into the fretboard or neck pocket to expose the nut and allow space for adjustments.
Like to hear your thoughts on my thoughts!