I used translate.google.com in order to translate the first post there --
For some time I have been working on a C128 version, which fits in the C64 case (slim case). I have some modifications built in like: VIC / VDC output switcher, Control port switch, 8 bit color ram, Accepts 6-36VDC input voltage, Dual SID, etc.
Here are some pictures of the project (still in the prototype phase):
EDIT: Pictures uploaded to the forum and inserted! External links removed! war64burnout"
Hmm...this part seems familiar: "The Color Ram is actually 4-bit in size and the VIC chip can only address 4-bit, there are only the other 4-bit for the CPU free, so you have seen another "bank". So does this increase the number of colors that can be output? Nope. It only gives you 4 more bits as a "buffer" and could thus swap between the upper and lower "bank". So are there any compatibility issues? Should not really, but nothing is 100%, if one modifies. (the upper bank is always set to signal high in the original)"
Honestly, they should have put sockets for the connectors on both sides. One spaced for the 64 case and one spaced for the original C128 case. It probably wouldn't have made the PCB cost much more either. A 128 in a C64 case is just wrong This would have been great for fixing 128s with damaged mobos, but now? It will just be a thing that eats the supply of rare chips for REAL 128s.
After reading all of the forum posts translated to English, I agree that the 128 keyboard or a re-creation of it would be more proper. The project seems to be very fluid right now, and the developer is making changes to it regularly.