This is one thing I've always imagined. Certain songs, while possibly good or even perfect for its respective wra, have a what could have been feel to it had it been recorded in a different period. Now I'm of the opinion that just about anything would sound great in a Pet Sounds sheen, but certain songs just seem like they would have been divine in another period and I can almost imagine.
A few that come to mind that I would have loved to hear...
Let's Put Our Hearts Together circa Pet Sounds
You're Still A Mystery circa Today!
Goin' On circa Sunflower
I Know There's An Answer circa Love You
She's Got Rhythm circa Surfer Girl
I can definitely imagine she's got rhythm as a mid-tempo ballad.
Let Him Run Wild with Brian's Love You Era vocals would be very good.
I can imagine the farty synths during the verse and more wobbly sounding ones during the chorus with the horns.
Girl Don't Tell Me would translate great with 20/20 Carl vocals
Hushabye with Al singing Mike's lead circa M.I.U. (totally hearing Lady Lynda)
Kona Coast to be be released in '63 on Surfer Girl
Slip On Through with Blondie in '72
All I Wanna Do around Smiley Smile era so it would be a little more experimental.
That's all I got for now