What might actually be awesome would be if you could map the buttons on the FM radio adapter separately. Then you could use that as a mini gamepad and make the hold button on that A and Play B or something.
I went ahead and ordered a cheap FM tuner for my ipod6g off of eBay.
I started playing with the keymaps for rockdoom (./apps/plugins/doom/i_video.c):
#if (CONFIG_KEYPAD == IPOD_4G_PAD) || (CONFIG_KEYPAD == IPOD_3G_PAD) || \
(CONFIG_KEYPAD == IPOD_1G2G_PAD)
#define DOOMBUTTON_SCROLLWHEEL
#define DOOMBUTTON_SCROLLWHEEL_CC BUTTON_SCROLL_BACK
#define DOOMBUTTON_SCROLLWHEEL_CW BUTTON_SCROLL_FWD
#define DOOMBUTTON_UP (BUTTON_MENU | BUTTON_RC_VOL_UP)
#define DOOMBUTTON_WEAPON BUTTON_RC_PLAY
#define DOOMBUTTON_LEFT (BUTTON_LEFT | BUTTON_RC_LEFT)
#define DOOMBUTTON_RIGHT (BUTTON_RIGHT | BUTTON_RC_RIGHT)
#define DOOMBUTTON_SHOOT BUTTON_SELECT
#define DOOMBUTTON_ENTER BUTTON_RC_PLAY
#define DOOMBUTTON_OPEN BUTTON_RC_PLAY
Keys left, right and play are addressable on the remote - this is really cool and its like having a Wii Nunchuk Controller for the iPod.
The only thing I haven't been able to get working is Up/Down (BUTTON_RC_VOL_UP/BUTTON_RC_VOL_DOWN).
I suspect that this is because of something that needs to be changed inside of ./apps/keymaps/keymap-ipod.c
I only really did this for a laugh and I had some spare time to play around with this today.
Though if anyone does have any ideas on how to address those extra buttons please do reply