As Armin wrote, no magic is possible: one signal, one chain, two or more components... impossible to tell one from the other w\o using any "foreseeing model".
Since using a flat amp doesn't return the wanted results for profiling cabs only, and since Till's cabs sound good as per most users, and are also versatile with other amps, this means that (there's a kind of rig (amps, settings, mic) which works best for getting a cab which is great-sounding, usable and versatile when used with other rigs.
In other words, we have to find the best approach to get the best cabs, and this depends on the above-mentioned foreseeing model. Maybe we'll find out that a Fender De Luxe returns the best ones, or something different.
I'm sure it's just a matter of time before someone comes across the optimal alchemy.