As for the chipset, this might sound crazy, but I have a suspicion that JVC might be doing the upconversion and videoprocessing in SOFTWARE. There is no dedicated upscaling chip on the entire PCB. The only processor of any kind is a rather large IC labeled ARM with a M on it. I'm assuming it's an ARM processor of the Matsu****a brand, but I could be completely off base. Also, on the underside of the PCB I found flash memory, when we know that the player has none available. It would make sense that the OS and firmware is loaded on here.
I'm suspecting that JVC basically gave us what amounts to a dumbed down HTPC here - literally everything is handled via software by a general processor (the arm unit). That would explain why the upscaling is so good, the bluray drive with a SATA interface, the realtek LAN, as well as to the generous codec support and fast loading times.
EDIT: Trying to expand the SATA port is a no-go, it won't read a hard drive in an external enclosure. I'm trying to find a female USB port I can cannabalize on an older piece of equipment I have laying around so I can add the internal hard drive.