AG Book Rounded could do the job, also

http://www.philsfonts.com/detail.html?sku=AB80303004P1

There's a typeface in the Solotype Catalog called Rolling Extra Bold, which Dieter Steffmann digitized as Rolling No One ExtraBold. As you can see, it's less rounded, but pretty close:

It's also been digitized by FontBank as "Rhythm".

.. but I prefer by far Peter Bruhn's Ketchupa.

This is an Alphabet Innovations font from the early '70s by Phil Martin called Fat Chance. I don't know of any digital version.

You could probably get a similar effect by stretching Helvetica Black Condensed horizontally and rounding off the corners with a filter or something.