Multiple emulator key binding - best practices?

[tdixpix]

I have an IPAC Ultimate in an arcade cabinet, and would like to use the following with Mame and RetroArch 

- Two 8 way 6 button digital setups (P1, P2)
- Up to 2 PS3 controllers (Xinput as X360)
- One Thrustmaster wheel (recognized as wheel, but could be mapped to joypad)
- One Dolphinbar with 2x wiimotes (used as real wiimote for wii games, and as a mouse for MAME shooters)

Any thoughts or best practice keyboard layouts? Walkthroughts that helped you, maybe? Should I say to hell with the whole thing and use a software like XPadder? 

I'm trying to create a key bind that works for all emulators is proving to be a huge headache.

Thanks for your input