Is「何だとう」a Japan-wide phrase or regional?

[Outkast]

I've been listening to one too many anime lately, and now I've got the expression "Nan da tou" or 何だとう stuck in my head. I suspect this to be a regional dialect phrase, but it may not be. Anyone know for sure?

[Jason]

The phrase is actually 何だと. The と tends to get drug out, so it comes out とう. It means "what did you say?" And no, it's not regional.

[Outkast]

Okay, thanks!