Major Motorola Droid Bionic update rolling out now; Download and manual install available - Android Approved : Let's talk Android they saved the file at Multiupload.
You might be able to look at posts here from around December 13th or so. Someone may have grabbed it. Do NOT use any that go to either 5.7.886 or 5.7.893 or any variation as they aren't what you're looking for. The file has to go from 5.5.886 to 5.5.893.