Did something close to this during my college days.
While making myself breakfast one morning, I poured myself a bowl
of frosted flakes cereal, then realized I was out of milk. However,
I was (and still am) a root beer fanatic, and had several cases of
A&W's in my fridge...
As I recall, frosted flakes in root beer didn't taste too bad,
actually. The only problem was the carbonation caused the flakes to
go soft real fast.
MG