I am convinced beyond doubt that the term 'full synthetic oil' is categorically and unequivocally a marketing term and nothing else, further more I am positive that one would more quickly find an honest member of Congress before discovering a -true- full synthetic engine oil.
A sincere thank you to all who responded.
There are plenty of oils that meet the definition of full synthetic.
By the BBB standard for the rest of the world, Group III is sufficient to meet the definition of "full synthetic", which is why you see so many oils labelled thusly on store shelves.
By the German standard, Group III is not sufficient, so the oil needs to be ~75% of Group IV or V, which includes PAO, AN's, Esters...etc. The remaining 25% is reserved for the additive package, viscosity index improvers (VII) and carrier oil.
That said, there is very little in the way of performance difference between Group III and PAO for the most part. While PAO has no wax, and thus insanely good cold temperature performance (and better oxidation resistance), as a blended product, a Group III-based product, particularly blended with other bases like PAO, will approach PAO-based lube performance at a much lower cost.
If your goal is simply to have an oil that meets the German definition, there are plenty available, even approved ones, like Ravenol. If approvals aren't your thing, Redline white bottle is also majority PAO with some POE in it.