This patch series does $SUBJ.
The first patch changes the way the existing linker scripts locate the boot page, reset vector, and bss section. This method works for any size of u-boot image (the previous one didn't work images that weren't 512K) and any location flash is mapped to.
At this point all the mpc85xx linker scripts are exactly the same, except for one line that defines the flash bank size, so they are combined into one script in cpu/mpc85xx/u-boot.lds. A common flash bank size that will work for all boards is used. If a board in the future needs something different (either very small flash or a very large u-boot), then it can easily be overridden by using a two line board/*/config.mk file that defines the flash bank size and then includes cpu/mpc85xx/u-boot.lds.
The next two patches clean up the common boot script some more.
I imagine there is more cruft in the script still, like the .data.init and .text.init sections that are 256 byte aligned but have nothing in them.