http://code.google.com/p/aeroquad/downloads/list
The code in question is AeroQuad_v2.1.2_Beta.zip
In AeroQuad.pde uncomment these defines to drive image over 30720 bytes:
#define AeroQuad_v18
#define HeadingMagHold
#define BattMonitor
That should give you a sketch size of:
Binary sketch size: 31574 bytes (of a 32256 byte maximum)
Which will fail to upload despite being below the 32256 maximum.