Hal 9000 said:
That seems pretty convoluted, and personally there was never a question about what color Anakin's saber would be. It's the saber that went to Luke, therefore it is blue. Introducing a red saber through fan editing adds a host of questions that need rationalizations, as you demonstrated.
I could live with thinking 'ol Ben must have changed the 'crystal' somewhere along the line after ROTS, for the impact the change makes - there's a lot that needs rationalized about the prequels as it is, and let's face it, he didn't seem to have much else to do stuck out in that old hut on Tattooine...except maybe sun himself, or hang out in the cantina a little too often. ;)
On the other hand, if George had just let Obi-wan hang onto that GREEN saber of Qui-gon's that he used to kill Maul with...then we could have had a contrast of colours in the duel with Anakin after all! :)