Will.....they are out there, but I suspect jealously guarded by their current owners.
12k for an unknown quantity in a huge risk, better off getting a known seized engine, untouched and doing a rebuild in UK. Are the Italians that bad at engine rebuilds?!
I know one or two other people to ask, but as a "newbie" I don't have the depth of knowledge, kudos and contacts others on the forum and in the club have, so might just come up short in getting the relevant answer!
As you say a tip off/private lead to an enthusiast whose in it for the love of the coupe is your best bet.
I know matching numbers is very important, but what truly are the chances unless a worldwide data base has been maintained of current known engines? Fine re known produced engines matched to produced cars, but will be a very long shot. The internet has its limits and in a Lancia Aurelia world of guarded secrets (Italian style), its not what you know but who you know.
Leave it with me and I will let Sherlock off the leash!!!
P