Hi there - the Vortex was a little ahead of the Litespeed curve in the switch to 1 1/8" threadless - IIRC the '99 was the first Vortex to do so, so the '00 was specced with an all-carbon threadless Reynolds Ouzo Pro fork. I managed to trash my original fork in a car-roof "garage door" incident, and spent many years scanning eBay until a NOS Ouzo Pro showed up, so this is an original spec replacement.
More relevant to your question, this year I bought a '98 LS Classic frame, originally specced with 1" threaded - not a fan of threaded, so if I was going to have to buy a fork, I wasn't going to go threaded. Fortunately, there are still 1" threadless forks out there - Ritchey makes one with an Al steerer (getting harder to find in 1" but still out there), but I wanted a straight-bladed fork to reflect the straight stays of the Classic, so I bought an Origin8 Synergy - carbon fork blades and steel steerer. There is a slightly more expensive Al steerer version (Synergy Pro) if you can find it. I'm sure there are others. I installed an FSA Orbit X 1" threadless headset. Both fork and headset from Amazon, IIRC. Pretty straightforward job, and well within the capability of the home mechanic.
Also take a look at this thread where I describe the Innicycle threaded to threadless conversion headset - this provides an almost seamless conversion to threadless at significantly lower cost than a new fork and headset
Edit: turns out that 2000 was the first model year for any of the LS road frames to go 1 1/8" threadless