I had to write this one out to see if you were correct, and although you were pretty close there is one flaw in your theory....the major 3rd of the 5 chord is not addressed in either scale...so in fact the combination of Cmaj blues and C minor blues would outline a G minor 7th chord.
I think the answer to trebledamages question is no...theres is no one scale that outlines the dominant 1 4 5 progression.