I've attached an example using blends for the corner areas - this retains some of the diamond-like pattern that is present in the original buttons.

If you wanted to reduce that, you would probably want to make the initial extrusion shape to have its middle area be flatter across a wider portion of it, the initial profile that I extruded was like this:



If you made the center flatish area to be a bit larger that would change some things about the resulting shape too.

But also sometimes it can be easier to do things that are puffy or blobby looking in a polygon modeling program rather than in NURBS, they are more focused on a kind of sculpting like mechanism which works well for organic shapes.

- Michael

EDIT: put in 3DM attachment that I forgot initially.