I do have in my possession somewhere in my record shelves a 1-song-per-side pressing.
Dusty Springfield singing Burt Bacarach's The Look of Love.
One side is 33 1/3rd and the other is 45.
Bought it used and very cheap, played it once, sounds very good.
Ezio, I do have a Classic Record 45 rpm box set of one side pressing.
After I had a slight warp cooked out of all 8 Lps I found no better then other well recorded 45 rpm Lps.
However I do like the one side pressing only because I can drop and remove the Lp on the platter without turning off the table's motor speed control each time.