The folks from Sandstone Media have volunteered to give several talks.
Responsive Design Using Zen Grids Brian Gervais will demonstrate two recent responsive websites, and discuss the flexibility that using zen grids and SASS brings, including arbitrary breakpoints.
Commerce Tricks & Tips Dan Carlson discusses some challenges he's run into building Drupal Commerce websites, and provides some tips and tricks for how to avoid some of them.
Collecting Lots of Data From a Client Winn Jewett discusses using Google Docs to collect and organize large amounts of data from clients. He will discuss using validation and cell linking to create a database-like collection of tables that even clients can use and understand.
Dual Git Repositories Todd Anderson will present a technique for splitting Drupal projects into two git repositories, one for Drupal Core, and one for the custom site files. He will discuss several advantages that result from using this technique.