Then two things. If the gingerbread uses a different kernel than froyo, how is it able to get past the locked bootloader? And why dont they base CM4 off of gingerbread?
1) The GB leak has it's own kernel, but we're able to load it because it is a leak of the official release. This leak must include in it the encryption code that "unlocks" the bootloader to load the new operating system. A "locked" bootloader simply means that access to it is encrypted.
2) CM
IS based off of GB. CM4D2 is not based off of the GB
kernel, it is still based off the GB Operating System though. (There is a video somewhere that CVPCS posted about how he went about doing this)