I've been looking at the reasonably nice looking range of lathes that Weiss Machinery make. They're available in the UK as the Warco WM-series variable speed lathes, or the DB-xV lathes from Chester.
Geared or changeable-belt driven lathes can have a big mechanical advantage at low speeds so they'll have lots of torque when cutting threads or turning big objects or bits of steel or whatever. These lathes have no such mechanisms and make do with purely electronic speed control. They do have noticably heftier motors (30-90% more horsepower compared to similar sized belted/geared machines), but is it enough when running at these low speeds?
I think the Sieg C4 and one of the 10x22 models also have variable speed BLDC motors. If anyone has any experience with these I'd be interested to hear about it!