Creating a shortcut containing this line to bypass the launcher and launch the game with more RAM does not work with the new 1.6 launcher:
"C:\Program Files\Java\jre7\bin\javaw.exe" -Xmx4096M -Xms512M -jar "C:\Users\USER\AppData\Roaming\.minecraft\MinecraftDev.exe" username password

Worked fine with the old launcher. There needs to be a fast auto-login alternative to this (already in development? ... I see a greyed-out button in the launcher saying this).