The optiboot just compiled uses baud rate 115200 (see code).
No matter what, after reset a led on ic pin 1(see code) should blink briefly. Does it do that?
We had better check each fuse bit carefuly first in order not to brick the chip. I can help with that later...
In meantime I flashed the optiboot just compiled for 644 into my sanguino rbk, it works well, I use this boards.txt to download sketches:
sanguino.name=Sanguino
sanguino.upload.protocol=arduino
sanguino.upload.maximum_size=63488
sanguino.upload.speed=115200
sanguino.bootloader.low_fuses=0xFF
sanguino.bootloader.high_fuses=0xDC
sanguino.bootloader.extended_fuses=0xFD
sanguino.bootloader.path=atmega644p
sanguino.bootloader.file=ATmegaBOOT_644P.hex
sanguino.bootloader.unlock_bits=0x3F
sanguino.bootloader.lock_bits=0x0F
sanguino.build.mcu=atmega644p
sanguino.build.f_cpu=16000000L
sanguino.build.core=standard
sanguino.build.variant=standard