I am in awe of people that can make such things.
That being said, hardware emulation like the Plus Too doesn't excite me. I guess because while it takes pains to replicate the hardware processes to run the software it doesn't look or feel like the original machine. It uses a PS/2 keyboard and a standard screen (I note that the aim to to add ports for the original Mac keyboard and mouse though).
As a vintage experience, does it add much more than a software emulator?
On the other hand, replicas that re-create the look and feel as well as run the software (I'm thinking of the Altair replicates here) are a different kettle of fish. Or hardware emulators you can sneak in an old case and screen to replace the mainboard. The machines still look and feel authentic even though the stuff hidden inside is not.
Other hardware things going on which I love to see are things like virtual disk drives. My
X-profile in one of my Lisas is one. It's hidden away where the Widget drive would be, so the machine still looks the same (I only wish they had added drive sound effects). The
PetDisk is another. It sits behind the PET so you wouldn't even know it's there. I guess the Mac drive Gavin mentioned is another, and there are many other devices out there. Drives are the hardest pieces of vintage kit to keep alive and it's great to see these storage options being produced.