Though I keep thinking of buying a cheap Breadbin C64 off ebay (if I can find one) to house a RPi - as I want my C64 to remain as-is (albiet not working, but not really looked to find out why) for sentimental reasons.
I might be interested in buying the guts if you won't be using them to repair yours, which I highly recommend. I don't know if there are any regional differences related to power, keyboard and the like. Shipping might also make it not worthwhile.
Hopefully the cases and keycaps will continue to be available when I finally get one. I prefer the look of the original, so I may end up not needing/wanting those after all.
WizardStan, directive0 hit on a lot of the reasons I like having the real thing. Unless I misunderstood you I imagine that the "new old machines" appeal to those with money and space to play "what if", and some may also want something with more potential than the originals had. This is not so different from my own interest in new hardware for old computers. This allows for modernizing the hardware to replace things that are so dated they are expensive or difficult to make use of (old floppies, HDDs, modems), or add new functionality while providing most of the experience that people are used to with these computers. I have the main Apple IIe I use set up under a modern HD LCD TV with a cable ready to be swapped, yet I almost always use my old monitor.
I am the same way when it comes to consoles. I prefer the original hardware and software (and I love cartridges), but I will use some new hardware (Everdrives) and software. Things like the Retron 5 are not really for me, even before the questionable stuff associated with that product. I think I would just go for emulators on my other computers instead, and either a USB controller, or an adaptor for the original controller. Things like the Retrode might be good for me. I have the consoles I want, though. For problems like those with the front-loader NES the Everdrive works for me since I only have to fight with it once, and yet I still swap carts sometimes because that flashing is part of the experience for me (although there were years after the neighbors and I got our NESs where we didn't have problems very often, and my current NESs are both far more picky than any I used when I was younger). As with the computers, Everdrives also add functionality such as Game Genie codes without using a Game Genie and further ruining the connectors, as well as allowing me to make backups of my saves, which I have so far only done with my N64 games. I could use an emulator instead of bothering with all of that, but that isn't how I played in the past. I even have an old CRT TV with a really rough picture...I can probably replace it for not much $$. I can also go for Virtual Console versions of titles that are available. I own a bunch of those, along with rereleases of some games. Those are good enough for some of my family who are more interested in just the games. I am interested in the overall experience. Virtual Console, emulators and my Pandora, as well as my USB controllers that I used when I played games with emus on laptops, are available when I just want to play a game.
I don't consider myself a collector, yet my collection probably makes it seem otherwise.
I don't really like the idea of rehousing something modern in an old case. Unless I am using a perfect emulator I am not going to get the same out of that experience. The closest I would get to doing that are things like the Apple2Pi or however they are typing it now. That isn't really very different from how things were done in the past. It does bring up another reason why I like old hardware: seeing how far we can push something old. It isn't for everyone. I don't fully understand why people want to emulate everything they do, other than that they don't own all the original hardware and still want access to the software. If it wasn't for the software they would probably only be using more modern stuff. When combining the restoring classic cars as directive0 mentioned, and seeing how far you can push the hardware you come up with something like a nerdier version of hot rods that we don't get to show off as much. There are people who do the same kind of stuff with modern cars and computers for somewhat more practical reasons, but usually with older stuff it is just for fun. Actually, I am pretty sure on the extreme end of modern stuff it is a combination of "for fun" and bragging rights.