Contador is an innocent man... for the time being, at least. He should be treated as such. He has been tried and acquitted. Whether or not you agree with the RFEC's verdict, you can't continue to penalize him for it.
The comparison to the Landis situation is not valid. Landis was stripped of the title he won at the event during which he tested positive. I don't think anyone would argue that Contador would NOT get to keep his 2010 TdF title. But the 2011 Giro, which he is competing at after being cleared of previous charges, will be his if he wins.
The comparison to Valverde's case is also not entirely valid. Valverde was competing while appealing a GUILTY verdict. In that case he was only continuing to compete on the technicality of the appeal, so if the ruling was upheld the ban would be retroactive and anything he won in the interim could be taken away.
My opinion: If CAS finds Contador guilty, the ban should go into effect as of the date of the CAS verdict, and Contador should be able to keep any titles he has won (other than the 2010 Tour, of course). Contador should be able to bargain for any "time served" before he was acquitted by the RFEC.
Bottom line: As of this date, Contador is an innocent man. As far as we know, he has competed fairly since that finding of innocence and should not be penalized after the fact when (if?) CAS overturns the verdict.