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This question from last year has a complete switchup of all non-pawn pieces on the board with all the pawns on the 4th and 5th ranks, The goal was optimize the amount of moves needed to reach the given diagram.
Here is a variation of it. Only four pawns have moved, the least needed to allow a swap of all 16 pieces.
Challenge: Find the least number of moves needed to get to this position.
It turns out that it can be done in 46 moves at the least. Although the pawns are flipped, this old puzzle provides a game that can easily be adpated to my positon.
- g3 g6 2. Bg2 b5 3. Bb7 Bg7 4. Ba6 Bb7 5. Kf1 Be4 6. b4 Bf5 7. Kg2 Nc6 8. Kf3 Ne5+ 9. Ke3 Rb8 10. Ba3 Rb6 11. Nc3 Qa8 12. Rb1 Qg2 13. Ne4 Re6 14. Rb3 Nf6 15. Rc3 O-O 16. Qa1 Rb8 17. Nf3 Rbb6 18. Rb1 Rbd6 19. Rc6 Bh8 20. Rb6 Kg7 21. Rb3 Kh6 22. Rc3 Kh5 23. Rcc6 Kg4 24. Rb8 Kh3 25. Rcb6 Rd3+ 26. Kf4 Rb3 27. Kg5 Rb1 28. Kh6 Nd5 29. Nd4 Nf3 30. Nc6 Bb2 31. Rh8 Rh1 32. Nf6 Bc1 33. Ng8 Ng1 34. Qg7 Qf1 35. Qf8 Qd1 36. Qd8 Kg2 37. Kg7 Kf1 38. Kf8 Ke1 39. Ke8 Bh3 40. Bb2 Bf1 41. Bg7 Re3 42. Bf8 Rb3 43. Bc8 Rb1 44. Rb8 Ra1 45. Ra8 Nc3 46. Nb8 Nb1