I put together a one-off Z axis upgrade. This one is standard Z axis length, not an extended length. The extrusion and rails are 200mm, giving about 4" of travel. It comes assembled with a modified DeWalt spindle holder. The adapter plate is made from corian (an acrylic material). I’ve used this particular plate and spindle holder for over a year with no issues whatsoever. The linear bearings, rails, 2080 extrusion, motor plate, bearing, screw, and upper knob are all brand-new. It also comes with a new 15mm belt & pulley set (includes the 20t pulley for the motor). Includes bracket to relocate the Z home switch, but you will need to source the screws & nuts to attach your switch. Other assembly detail includes rails that are keyed to the extrusion slots where 4 screw holes on each side are fitted with assembly keys that perfectly center the rails to the extrusion slots. The only thing you need to disassemble from your existing Z axis is the motor & home switch.
Price for this setup is $250 plus shipping.