Stereo, hi fidility, ultra hifidelity ?

"Stereo" and "High Fidelity" or "Ultra-High" fidelity are totally different issues. A high fidelity record may be mono as well. Can you imagine that imaging and the stage can be accomplished through the mono with the great success!
I do collect mono records and know how they worth. A lot of older hifi lovers will tell you that true fidelity is in mono records.

The pressing and mastering technology had been changing throughout the vinyl history along with recording as well.
Whenever the new technology was developed the consumers market have to act accordingly so by acheiving some descent sound from mastering by the mid-50's the "high fidelity" was placed on almost all records since they sounded better than previous ones.

Patrick, about your note for a "good hint": I've personaly spoke with Jimmy Page's recording engineers and they told me that it's very difficult to manage a live recording with Jimmy Page since he's getting too agressive during concert and often forgetting about being recorded starts to hit strings too hard that none would normally do with electric guitar. Alghough I do consider Jimmy Page as an excellent guitar player.

As to your list of recommended recordings I would add the whole ECM label. These vinyls mainly digital but very good mastered. ECM label is for free-, avant- and other kinds of non-traditional jazz. Also bite some EG label recordings too.