This article is from the Anime FAQ, by Steve Pearl with numerous contributions by others.
There was going to be a "Quantum Leap" ep in which Sam leaps into an animated character, and the animation was to be done by Katsuhiro Otomo of "Akira" fame. Sam was *not* going to be leaping into Akira. If you saw clips of "Akira" on any NBC promos during the Olympics, they were probably put there for the benefit of anyone familiar with Otomo. The actual ep would've consisted of original animation, animation that probably didn't exist at the time of the promo, hence the Akira clips. (Consider this: Do you really think that Streamline *and* whatever Japanese company that owns the rights to Akira would've let NBC meddle with "Akira"? Yeah, right.)
Now that Quantum Leap is cancelled, the only prospect for new Quantum Leap adventures is a possible movie a few years from now, and it is doubtful that this will be done using the animation concept. Oh well.