Replica 1

The Replica 1 is a clone of the Apple I designed by Vince Briel with permission from the Apple I's original creator Steve Wozniak. The Replica 1 is functionally a close copy of the original, but it is designed using much more modern parts on a smaller, simplified board design. The Replica 1 is designed around the same MOS Technology 6502 chip used as the core of the Apple I. Like the original, the Replica 1 utilizes simple AV in/out to connect to a television or other similar screen, and it maintains most of the original's functionality, such as the lack of a "delete" key. 
Apple had no objection to the project since Wozniak had given his approval and the design is technically Wozniak's alone since it predates the company itself. Apple had previously released all materials regarding the Apple I to the Apple I Owners Club.
Briel Computers sold the replica in two models, one pre-assembled, and another as a build-it-yourself kit. It appears the units (kits or otherwise) are no longer available at time of writing. 
Earlier revision Replica 1 came with an available Serial I/O card which allowed programs written on or for the Replica 1 to be stored on the hard drive of any common PC. This was needed because the Replica 1 had no other ready means of program storage, since cassette drives (the Apple I's storage device) are in short supply. The I/O card can also be attached to original Apple I computers.
The most recent model of the Replica 1 is the Replica 1 Plus, now sold by ReActivemicro. The Second Edition model integrated both the previous Serial I/O board plus a new USB interface into the main board. Other improvements included a wall mounted DC power supply replacing the previous model's reliance on a full PC power supply and a power on light indicator. The Third Edition model removed the USB interface and replaced the AVR microcontroller used to generate video with a Parallax Propeller chip. The Replica 1 Plus allows for a direct connection to the USB port on a computer for power and programming, and the addition of 2 ROMS mean that the user can switch between Apple 1 Basic or Woz monitor and Applesoft lite.
The Replica 1 includes Apple I BASIC in ROM to allow quick and easy programming, as well as the KRUSADER Assembler that provides a powerful symbolic assembly programming environment, including a disassembler and a low-level debugger.
The Replica 1 is not available for purchase on Vince Briel's website anymore and is now sold by ReActivemicro.
Interfacing capability.
The Replica 1 contains additional expansion ports for added system capability, these include:
Used for interfacing with a home computer running a terminal emulation program, such as HyperTerminal for Windows, or ZTerm for OS X. This allows for quick data inputting for large programs, which is favourable over typing in such programs by hand. 
Used for connecting original or third party expansion boards to the Replica 1, such as the CFFA1 Card Reader and Multi I/O Board by Briel Computers.
Used for memory expansion boards