This seems to get player one working properly with a xbox 360 gamepad under mac using 0.12 of
http://tattiebogle.net/index.php/ProjectRoot/Xbox360Controller/OsxDriver

/Users/<mac-user>/Library/Shadowgrounds/profiles/<sg-user>/Config/keybinds.txt:

// Extra padding for loading

joystick_move_x_axis = axis_x
joystick_move_y_axis = axis_y
joystick_dir_x_axis = axis_rx
joystick_dir_y_axis = axis_ry
controller_type = 105
camera_move_forward = i
camera_move_backward = k
camera_move_left = j
camera_move_right = l
attack = joy-but-10
change_next_weapon = joy-but-4
quit = esc
camera_look_mode = joy-but-15
screenshot = f11
special_move = joy-but-7
console_toggle = f8
change_prev_weapon = joy-but-3
reload = joy-but-12
flashlight = joy-but-8
execute = joy-but-14
attack_secondary = joy-but-9
run_script_9 = f12
weapon_1 = 1
weapon_2 = 2
weapon_3 = 3
weapon_4 = 4
weapon_5 = 5
weapon_6 = 6
weapon_7 = 7
weapon_8 = 8
weapon_9 = 9
weapon_10 = 0
open_upgrade = joy-but-5
open_map = joy-but-11
open_log = joy-but-6

For player two, buttons and everything would work the same way (using joy2-... instead of joy-...), but the axis don't. So instead I just used just keyboard and mouse:

// Extra padding for loading

joystick_move_x_axis = axis_x
joystick_move_y_axis = axis_x
joystick_dir_x_axis = axis_x
joystick_dir_y_axis = axis_x
controller_type = 101
camera_move_forward = w
camera_move_backward = s
camera_move_left = a
camera_move_right = d
attack = button-1
change_next_weapon = q
quit = esc
camera_look_mode = alt
screenshot = f11
special_move = shift-l
console_toggle = f8
change_prev_weapon = z
reload = r
flashlight = f
execute = e
attack_secondary = button-3
run_script_9 = f12
weapon_1 = 1
weapon_2 = 2
weapon_3 = 3
weapon_4 = 4
weapon_5 = 5
weapon_6 = 6
weapon_7 = 7
weapon_8 = 8
weapon_9 = 9
weapon_10 = 0
open_upgrade = enter
open_map = tab

Related links
http://shadowgroundsgame.com/new/index.php?page=gamepad
http://shadowgroundsgame.com/help/shadowgroundsgamepads.php
http://frozenbyte.com/board/viewtopic.php?f=8&amp;t=2180