Yuji Naka confirmed that the Wii version is the original version. They finished it but couldn't get it published if I recall, but then they made the DS version and half-way they started on the Mobile version, which of course they self-published, probably why that's the first one we saw, and the success(?) of it got Bandai Namco to sign on the other versions.
I have to wonder, it was reported that Naka was underway with an "Action game" for the Wii of sorts at the beginning, but during development he discovered that the Wiimote can pickup tap motions, thus Let's Tap was born.
Could Ivy be that Action game?
In other news, Naka confirmed in a few interviews that he's underway with two bigger projects, one which is an action game using a new control scheme of sorts, the other is based on a real-world activity.
In another interview he mentioned one is using a new animal character with a theme based on the sky.
My bets are this being the new control scheme game, OR perhaps it's sort of a Wing Island thing and it's the latter where it stars a bird flying an aircraft, could be a hang glider for all we know.
Edit: Unless he was trying to hide something, Ivy was NOT that original action game, it never made it to development:
http://play.tm/interview/23282/yuji-naka-on-let-s-tap-and-beyond/
You mentioned that the idea for Let's Tap originated while you were working on an action game. Does this game still exist or has it since been scrapped?
The game never made it to development and it's unlikely it'll ever come out.
