I don't really think it is BIOS issue.
OS can do it just fine on its own. I don't see why BIOS should be invovled here.
Has any work been done toward the goal of "Hibernation"? I'm writing of the type that would use a separate partition equal to ram + swap space to store the current memory state. If no one has done any work to this effect, how difficult would it be? I may be willing to help the effort. I've never programmed for a BIOS, but I've done mmap() stuff before.