Just heard the Prairie Home Companion's show with Inga Swearingen. Corrected the lyrics from above.

Hush little baby, Don't you cry,
Mama gonna make you some rhubarb pie.
If that rhubarb pie's too sour,
Mama's gonna pick you a wild flower.
And if that wild flower wilts,
Mama's gonna buy you a pair of stilts.
And if that pair of stilts ain't steady,
Mama's gonna make you a bowl of spaghetti.
Scatting...

And if that spaghetti's not al dente,
Mama's gonna buy you a horn of plenty.
And if that horn doesn't have the wrong fruit,
Mama's gonna buy you a two piece suit.
And if that suit's not the right material,
Mama's gonna feed you a bowl of cereal.
And if that cereal's not low carb,
Mama's gonna feed you some more rhubarb.
So hush little baby don't you moan.
It's been 30 years on the Prairie Home.
Some scatting….


Such a sweet, sweet version. Also can be heard at Prairie Home Companion's May 15 2004 show archive