Sweep/ bend object

How would I have a shape arch on one end and then smoothly blend to be flat…Sry i cant think of a better way to phrase it. Basically I have multiple objects joined, so there are gaps, and i want to curve the surface two ways and blend them. I couldn’t get it to work with the curve modifier.

Like this

http://cdn.electricpig.com.s3-external-3.amazonaws.com/wp-content/uploads/2010/03/Arc-Keyboard-1.jpg

The object I have are the keys


You could try a lattice.

Thanks, works perfectly.