Few drivers have ever existed that compete with the Fostex F200A IMO: 30 -20,000 Hz, 90 dB/w/m, 8 ohms, huge AlNiCo magnet, machined aluminum frame. Perhaps some European exotics (expensive) back in the day might have gotten close. And I've been a transmission line fan for 40+ years, so commissioning Bob to build the M18-F200 (at his prices) was a no brainer. Since then I had Bud Purvine EnABL the drivers (he invented the process) and have added, thanks to Duke LeJeune, Late Ceiling Splash tweeters (cheap Dayton Audio units on the floor behind the M18-F200's with a cap added in parallel). These upgrades improved clarity and high frequency response while expanding the soundstage.
TB didn't exist in 2003, neither did Tekton or Mark Audio. AN seems to have come a long way, was much taken by the 3 inch driver in a ported cabinet (for true desktop use and even small in-room use maybe adding a sub). Back then Common Sense Audio sold only Lowther and mainstream Fostex drivers. Their cabinets were very poorly braced and David Dicks would only audition in his room (where he reportedly hid the use of tone controls). Tried briefly once to set up a small audiofest with him and others but he wouldn't travel, then he threatened to sue me.
If I had to build/buy single driver speakers today, it would be a choice between TB, Tekton, Mark Audio, Omega, or E. J. Jordan. I'd compromise and go smaller, roughly 5 inch, probably sealed, with add multiple sealed subwoofers.