As others noted, when I looked at this, I noticed the same thing: It seems as if the "lens holder", and the OVF/flash is simply a "cap", that you lock onto the main body. To me it seems that the body is not formed from a single piece of plastic or metal.
As others noted, there are technical difficulties with this, i.e. I would be surprised if the users themselves can simply lock on different "caps"/adapters.
But what about Ricoh/Pentax themselves? This modular design would allow them to offer, (for example), two versions: the one shown here, and another one without the OVF, making it even less bulkier (think K01 replacement too

)...
So maybe the users cannot use different adapters themselves, but Pentax/Ricoh would save on resources by offering the same "main body" and a few different adapters to lock on to it.
Just a thought...