RSH up just on short sell covering which was about 16 days worth of daily volume. Otherwise nothing good about RSH and no good news. It will go back down although may or may not go BK.
In the other hand Sony is a completely different story of a company on the cutting edge of smartphone and tablet as well as TV technology (not to mention movies, PlayStation, etc). The only problem with Sony's stock is, as you mentioned, it is an sleeper right now which to me is actually a good thing as it has and continues to give long chance to accumulate before shares really go up.
With Sony we've had 3 upgrades just in the last few short days and even before the give their earnings numbers. As a matter of fact the good news and upgrades have been pouring in so rapidly it has been difficult to keep up with. The ONLY reason Sony is still trading only 50% above their 52 weeks lows while others far less worthy companies such as RIMM and NOK are up over 300% is just what you had said (SNE is currently an sleeper).
Sony need a big day of say 25% or more jump on more than triple average daily volume for the market at large and momentum crowd in particular to notice it (no more sleeper) but then after that it will be very difficult if not impossible to catch up with it.
Bottomline is that SNE is a long term hold kind of jewel and one of the best finds in the hot area of the market (Smartphones, etc) and there no others that come even close.