It's a clever design (the one in red is my favorite) and it would certainly work very well in small sizes, and I could even see it work as a website animation with it appearing gradually left to right as if it's being drawn and then the "i" dotted at the end.
But I don't know if I'd see it as a "vi" unless I already knew what it was. Have you tried putting a slight separation between the letters, or making the letters overlap rather than join, or maybe the "v" in black and the "i" in red? Of course those ideas would also disrupt the flow of the logo, so I'm not sure if they'd help or hurt.



