I live in the southeast US. I first started hearing "flustrated" by local speakers a few years ago. It was apparent that the speakers were not using this for comic effect; the speakers were quite angry at the time.

I don't think that it's a combination of flustered and frustrated...just a variant pronounciation of "frustrated". If you look at the examples used by the other contributors on this site, I think that they illustrate the use of this term as "frustrated".

A swimmer

Flustration is wrongly spelled Frustration.

This mistake possible came from the attempt to join words frustrated and flustered which is senseless.

See other translations.
(Note: they are wrong.)

1) To become frustrated and flustered at the same time cauz you cant get what you want 2) to be like Neil

Flustered & Frustrated combined into the one word to describe a combined feeling of both emotions.

To be frustrated and flustered at the same time.

A made up word apparently by southerners, which combines "frustrated" with "flustered"