MM Phono cartridge

For several years I used Clearaudio's TOTL MM cart, the Charisma II, which you should be able to find for somewhat less than the list price of $2K or so. I used it in a Technics 1200G TT with a Herron Audio tube phono preamp. I enjoyed it a lot, but accidentally broke off the stylus, and traded it in on a Hana Umami Red MC (which cost twice as much), which really does sound orders of magnitude better to my ears and my gear. 

For what you're looking for, I'd definitely look into the Charisma II MM. The Music Room is a great place to start, but there are many others who sell wide variety of carts. 

I second the Nagaoka recommendation. Is the Zephyr not satisfying you or is this because it is due for a rebuild? I adore my Soundsmith cartridges but they are outside your price range.

Get a Stanton 681EEE. I have one in my collection.

The Zephyr is getting long in the tooth.  So I was contemplating a change vs a rebuild.  If I were to change, it would be to find a bit "rounder" sound.