I think I know the fellow you're talking about, but unfortunately I don't recall his name. If I do I'll be sure to post it. His solution required one to donate their outer axle end so he could salvage the u-joint yoke (provided the yoke was in servicable condition). He then welded this to his new axle end which, instead of a spline, transferred torque to the hub via a fitted shaft with four keys/keyways. The axel ends and hub were apparently made of improved materials and improved design that didn't suffer the Europa axle breakage syndrome.
It seemed like a robust solution, and I have considered it myself. I was, however, reluctant to give up two perfectly good axle yokes for this endeavour. I was also somewhat concerned about the potential lack of engineering involved. In this world of over engineered everything, and the resultant cost increases of it all, I can be satisfied with a bit of diligent home grown, eyeball engineering. However, the method of transferring torque with four keys is quite unorthodox. Two keys placed 90 deg apart is generally sufficient in moderate to high load applications, and given the low weight of the Europa should be suitable for this application. The four keys was a small warning sign to me regarding the potential lack of engineering knowledge behind this solution, but my concerns may be completely unwarranted. For all intents and purposes it does appear to be a workable solution. I'm certainly interested in hearing from anyone who has fitted these parts to their car.