The version I've heard of this song, in Australia, was brought to us by Dave Alexander, a wonderful mountain of a man who's no longer with us. More's the pity.

I don't have the words to hand but my recollection of the opening verse is;

He was only a lavender cowboy
He'd only three hairs on his chest
And he rode on a filly
Called Daffy Down Dilly
The sexiest horse in the West
Tra la la
The sexiest horse in the West

It got to the stage where that verse was used as a chorus but each verse ended with the Tra la la refrain.

It also included the verse posted by JimmyC (above) and copied here with appropriate modification.

And when they had him surrounded
The sheriff stood up and he said
I'm coming to get ya -
Oh goody I'll let ya
The lavender cowboy replied.
Tra la la
The lavender cowboy replied.

Cheers, Rowan