Which are the 6 AM models you've tried and what are you willing to spend? This info might help.
As far as SS tuners go, besides the Fanfare, the Audiolab 8000T has an excellent AM section (and FM section) but is costly. The AVI S2000MT is reported to have a well-designed AM and even Shortwave section but it is also pricey and hard to find. I'm sure you know the Carver TX-11a comes with AM section but I don't think its anything special in terms of sound quality.
Your best bet might be a good old tube model with a decent AM section, but I don't know which are best though owners of the Dynaco FM-3 and Sherwood S-2200 have said they have good AM. Even the better vintage SS tuners with AM/FM are probably vastly superior to most modern AM sections. For example, the Accuphase T-100, Sansui TU-X1 and possibly the cheaper TU-919 or TU-9900. The Denon TU-680NAB also has an excellent reputation for AM sound reproduction.
These are some possibilities.