Google just pushed an update v4.1.2 to the Gmail app (up from 4.1.1 and 4.0.5) that brings a few enhancements to Android 4.0+ devices, including improved support for 7" tablets. The full changelog for this update reads as follows:
Android 4.0 (ICS) and up:
- Improved 7" support
- Bug fixes and performance improvements
At first blush there don't appear to be any visual alterations, so we'll just assume that most of these enhancements take place under the hood.