Word is that the film version would be directed by Ju-On (The Grudge) director Takashi Shimizu, so I guess we're talking about a Japanese film, not a Hollywood flick. Yeah, I dunno if the US mainstream would be as interested in a roller blade-bearing serial killer(/assailant).
Now: how likely is this to be true? Well, Japan loves its live-action flicks, and it also loves Satoshi Kon, so it's not hard to imagine that a work he directed might get tapped for something like this. However, there's absolutely no source listed on Bloody Disgusting other than the site itself, and the last time we got a rumor from this site, it was about how the live-action Akira was dead in the water-- which has yet to prove true or false. (Though they did break the original news about the Akira flick as well.)
So, I guess I'd rank right smack in the middle: on a scale of one to ten, 1 being "totally not happening" and 10 being "well, duh," I'd give it a 5: perfectly plausible, but there's no real evidence or proof I can analyze either.
What do you guys think? Would you be interested?