This goes straight to my Christmas wish list!
But instead of a crippled Cyanogenmod I'd rather see dual-booting to Ubuntu and perhaps some Linaro builds. Staying close to Samsung SGS3 stock, may be a good idea for compatibility issues.
USB3 + HDMI + Front-facing Cam + JTAG over USB support
(1149.7, NIDnT) + possibly UART HW debug
But perhaps more importantly, everything should be easily accessible from outside your platform so we can help hacking it back into shape when something goes wrong! Second, make sure we can freely mess with the boot configuration... I'd be happy to help sponsoring the low profile SMT DIP switch for boot config.
If you have space problems you should seriously consider using a quad-core (Krait) Snapdragon S4 Pro
) PoP SoC instead. Because if not, you'll need external modem support. So in your current configuration, what modem are you using? If you use the Intel XMM6260
you'll need a lot more support components, AFAICT, unless their new flagship (XMM7160
) has managed even more integration somehow.