The -eroo suffix works as an intensifier of sorts, though it also seems to have other, less well-defined properties.

The online OED has only this to say about it:

-eroo, suffix
  factitious slang suffix as in boozeroo n., brusheroo (brush n.2 8b), flopperoo n. U.S. formations
  in -eroo, -aroo (e.g. buckaroo n.) are discussed in Amer. Speech (1942) XVII. 10f,
  and in T. Pyles Words & Ways Amer. Eng. (1952) 199.

1964 Guardian 8 July 7/6 Those jerkeroos feel embarrassed.

Etymonline's gloss is similarly disappointing:

switch (n.)
The meaning "a change from one to another, a reversal, an exchange, a substitution" is first recorded 1920; extended form switcheroo is by 1933. (Emphasis my own.)

I would like to know where this suffix comes from and, if possible, why there isn't a better etymology. Any ideas?