Hi Ian,
I don't know that one exists. You can get a general idea of what some dropped names are going for by participating in the drop auctions, but I haven't seen a combined list showing winning bid prices from different registrars - that info probably wouldn't be shared I don't think.
The closest thing I've seen is that Sibername lists the past week results showing which registrar "grabbed" the dropped .ca domain - no price info though.
Cheers!