m3.xlarge and m3.2xlarge sizes don't include ephemeral disks

The m3.xlarge and m3.2xlarge hardware types in the ec2 API don't include the ephemeral disks, which is particularly annoying because the only way you can get ephemeral disks on an m3 instance in the first place is to explicitly specify them when creating the instances. So if you're relying on the hardware definition to tell you what volumes to add, you're going to be out of luck.