I just noticed some products I hadn't seen before: wide-angle lenses for FPV cameras:
150 degree FOV
http://www.hobbyking.com/hobbyking/store/__21283__2_1mm_F_2_0_Turnigy_Micro_FPV_Camera_Lense.html
130 degree FOV
http://www.hobbyking.com/hobbyking/store/__21285__2_5mm_F_2_0_Turnigy_Micro_FPV_Camera_Lense.html
115 degree FOV
http://www.hobbyking.com/hobbyking/store/__21284__2_8mm_F_2_0_Turnigy_Micro_FPV_Camera_Lense.html
150 degree FOV
http://www.hobbyking.com/hobbyking/store/__21283__2_1mm_F_2_0_Turnigy_Micro_FPV_Camera_Lense.html
130 degree FOV
http://www.hobbyking.com/hobbyking/store/__21285__2_5mm_F_2_0_Turnigy_Micro_FPV_Camera_Lense.html
115 degree FOV
http://www.hobbyking.com/hobbyking/store/__21284__2_8mm_F_2_0_Turnigy_Micro_FPV_Camera_Lense.html