Here's a story that Paul Pratt wrote about on the Mini vMac site:
It is an effort to build a replica of a Macintosh Plus:
"The retrocomputing world is full of emulators for popular computers of the past. These emulators are software programs that run on a modern PC, providing the user with the same experience they’d get on the real computer. While some emulators may require a ROM data file from the original machine, they are still pure software solutions, requiring no special hardware. In the Mac world, programs like Mini vMac, Basilisk II, and Sheepshaver fall into this category.
Less common are hardware replicas or clones of classic computers. These are physical pieces of hardware that you need to build or buy, and that function just like the classic computer they’re based on. This category can be broken down further into what I’ll call physical replicas and functional replicas. A physical replica uses most or all of the same hardware as the original machine, and provides all the same I/O options, allowing for the attachment of vintage peripherals. The Replica 1 copy of the Apple I is a good example. A functional replica, on the other hand, works like the original machine but is not built like one. It probably contains an FPGA or microcontroller, and uses modern I/O devices like USB or PS/2 mice/keyboards, VGA monitors, and memory cards. Plus Too falls into this category, as does the Minimig Amiga replica."