As I said before, with the proper materials the concept is still sound. If you look at a 2 piece driveshaft like on a long box S10, the joint is not inside the tranny, its only lubrication is by 1 little 'ol grease zerk. If it will work for this application it would certainly work on a steering shaft.
As for "nobody makes it", that's a desperately lame excuse. Everybody here who does there own work could come up with at least a dozen parts/tools that they wish somebody would make. The fact nobody does it is usually a sign that it's felt they can't sell enough of them to make it profitable. I'd bet that at any major rod run, if you polled the people there, you would find 80-90 percent of them have never even heard of this setup. Also, it would be very dificult to make such a setup that would work for a majoity of applications because of the differences in columns, engines, exhaust, etc.. Also there is no overriding need for this setup as there aren't any design situations that I've seen where this was the only method that would work. Vega cross steering and the **** box steering the left side will usually do the trick. The only reason I know for the guys doing this setup was a personnal desire to simplify the engine compartment as it made it easier to route the exhaust and place the motor mounts for their situation.
opinions based on physical evidence are called facts.
