Great Scott!

[Douglas G. Wilson]

>Questions: Which well-known general could this be?

Gen. Winfield Scott.

>And does this seem reasonable as the origin?

Reasonable, but I wouldn't believe it without better evidence. There are
other people named "Scott".

I would also consider possible an origin from German, e.g., from the
conventional southern German greeting "Gruess Gott".

In any case, I believe the "Scott" is functionally a euphemism for "God".

I presume that the Great Scot variety of potato is more recent?

-- Doug Wilson