First, I do not have one of these printers, so I may be completely off base. However, there is an interesting thing I noted about the R3800, judging by its external appearance: The ink cartridge bay has enough unused space that three more inks (and only three more), e.g. R,G,B, could be added without redesigning the bay. I don't know if there's room for more inks behind the fascia. Perhaps Epson changed its plans, or was thinking ahead.
Don't you just love completely unfounded rumor and speculation? Someone with one could comment better.