I haven't seen any statistics that said turnout for Independents and usual non-voters was higher than normal.
Go to the Phew research website, they point out the exit polling facts that show independents and swing voters coming out for the Democrats.
The statistics were, 29 million voters voted Republican, 35 million voted Democrat. The numbers were down 22 million for Republican compared to '04 and down about 12 million for the Democrats. This clearly shows that 10 million voters switched party lines.
You don't have any proof that "conservatives stayed home" either too.