Why Ellison sat on LDV is whole life will be an utter mystery, but reliable rumor is he still has all the manuscripts in a box somewhere. I seriously doubt any legal battles will come about. He could have been sued multiple times over this, but no one ever bothered and most authors who asked for their stories back either got them back or Ellison paid them more money with a promise the book was still coming. It's possible his widow will simply give the stories back to anyone who wants them, but who knows.
THere is no reliable evidence that the collection even exists outside of the physical manuscripts collecting dust somewhere. There's no proof he was ever actually putting the book together or writing intros/editorializing at all, and considering that the promised edition of LDV Ellison touted would likely be somewhere in the range of 8-9 million words, I seriously doubt it will see the light of day as a serious publication.

good usage of "jarndyce v. jarndyce", touch literary tips

Ellison has stated that his instructions to his wife upon his death was to take all his unfinished manuscripts, unpublished work, notes, etc. out of his office and then burn them so that no one could complete any of his work without his approval.