Only a few Kenbak-1 were produced and even less survived. Over the time more and more Kenbak-1 Replicas were build.
Almost exact replica, replica using the same case but modern Arduino computer inside and replicas using modern computers in a small case.
In addition some emulators exist.
The first ever made replica was made in 2007 with permission of John Blankenbaker by Grant Stockly from Alaska, USA. It was a very accurate and good work. It is a full size case, a replica of the original PCB (mainboard) using old computer components. For the power supply Grant used a modern version.
It was a kit and the buyer had to built the Kenbak-1. I had a brief contact. He is not offering the replica anymore.
The website is still online KenbakKit.
A replica in small case with modern computer inside is offered by Adwater & Stir. µKENBAK-1 KIT.
Same guy made a full size replica with modern Arduino computer inside. The case and front panel is very accurate.
Full size Kenbak-1 kit.
Another replica in small case with modern computer inside you find here: Kenbak Mini.