What do you mean by regular Reo? The first Reo? That was the Woodvil and quite big because of big battery and wood is bigger than aluminium.
Regarding the aluminium Reos, the coming 18490 will be slightly bigger than the Mini. But according to the pics, it will maybe possible, that aluminium Mini and 18490 will have the same doors. But Rob said one time "No". It is still a development process. Because I am bound to APPLE since 1984, I call it for myself in the meantime "Reo Mini 2nd Generation with 18490 battery".
It will be NEARLY the size of the Mini, but not a big step like from Mini to Grand.
Andreas