Do DDR3 SODIMM modules come in sizes greater than 8GB?

Yes, they only recently did.

However, if you are using an Intel processor from 2013 or earlier then you may not be able to utilize 16GB sodimms.

The only exception is the Atom C2xxx series Avoton.

The i3, i5, i7 Sandybridge, Ivybridge, Haswell processors all can take only 8GB UDIMMs or SO-DIMMs.

Not sure about the latest generation of Intel processors though.

On AMD platforms, the Intelligent Memory 16GB modules are said to work fine.