I can't find it for the life of me -- this new search function is bringin' me down -- but there was a thread a while back about songs that people thought sounded "McCartneyesque," and so I saved the lot of them because I thought, as a working producer, that if I ever got the chance to work with Paul, I would propose a double-album called Is It Me?
Disc 1 would consist of Paul and several Paul soundalike vocalists (and I'm not talking Paul plus every tribute act ever, I mean "name" people like Andy Partridge ["I'd Like That" is a good example] and others who have been described as sounding close to Paul) performing original material written by Paul, both classic and new, same production style, same everything, and you have to guess whether or not it's Paul on lead. Think The Art of McCartney, but with the added fun of a guessing game.
Disc 2 would consist solely of Paul, but it would be he and his band recording their own arrangements of songs that were classically tagged as "McCartneyesque." If you were ever confused about whether or not it was a Paul tune, it'd be on there so now you weren't wrong! And for my potential track list, I filched a lot of ideas from that thread. I'll toss a few in here when I can find the list.