If you don't mind a used, older machine, Dyna Mechtronics had a couple of benchtop models. Seems like most owners change them over to newer electronics, even if the originals are operational, same for the Dyna Myte lathes.
Light Machines Corporation made the proLIGHT 1000, 2000, 2500 and Benchmaster. All the same machine, with varying motors and control. Unlike so many of the heavier benchtop CNC mills these were American made, their own design instead of generic Asian castings underneath. Instead of dovetail or box ways the proLIGHT uses round linear bearing rails on all axes.
After discontinuing that line of beefy machines they produced the SpectraLIGHT series, yet another weedy Sherline based setup.
The 1000 used steppers and an external control box that connected to a proprietary ISA or PCI card. You definitely want all that hardware or you'll have to toss what's left other than the motors and fit new controls. The PLM1000 has Windows software (or DOS if you want old skool).
The PLM2000/2500 have all the electronics in a single box on the back and connect to a computer via a single RS232C cable.
The PLM2000 could be had with a 5000 or 10000 RPM belt driven spindle. The PLM2500 had a 42000 RPM direct drive spindle but for some reason the only software available for it and the 2000 was for DOS, unless LinuxCNC supports it. I dunno what's different on the Benchmaster version.
Intelitek bought Light Machines and has all the manuals and software as free downloads.
Video of my PLM2000 I just got running.
Used an old MicronPC laptop booted off a USB floppy drive. Perversely, the only old laptop I have with a built in floppy drive
does not have a serial port. Software and manual links in the description.
Denford, in the UK, made a mid sized benchtop CNC mill and lathe. The lathe was the ORAC, built around Compact 8 clone castings. Dunno what the mill was based on. They also had a larger CNC lathe called Easiturn, which seems to be quite rare, especially in the USA. They they tossed all that and, yup, you guessed it, regressed to the wee little Sherline extruded aluminum equipment.