[allset_]

No, but clients do advertise how much of the torrent they have, so you can glance at your peer list and if you have 2 peers stuck at 10%... there's a good chance that you won't get more than 10%.

[ethbr0]

Yeah, and while current peer % is useful, it doesn't answer the other user question of "What percent of this thing has been seen anywhere recently?"

Which seems a pretty reasonable question for a user to have, if we're talking about fully decentralized torrents without a tracker.