Humdinger

What is the origin of "humdinger" which is used to imply a "big deal" or some sort of extravagance?

According to Merriam-Webster Online:

Main Entry: hum·ding·er
Pronunciation: 'h&m-'di[ng]-&r
Function: noun
Etymology: probably alteration of hummer
Date: circa 1904

a striking or extraordinary person or thing

The definition for hummer is just "one that hums", but I am not sure what that has to do with it. The American Heritage Dictionary lists the etymology as "unknown".

Hum may have come from an old dutch word for bumblebee and ding for to strike. Is humdinger like a bee sting?

"Ding" also means a ringing noise. Maybe "humdinger" comes down to "noisy noisemaker."