I see a feasible scenario where BYU goes 12-0 in the regular season, and then loses a close battle vs. Colorado in the Big 12 title game. They finish the season 12-1.

In this scenario, Ohio St. beats Oregon in the Big Ten title game (though if the opposite happen, you'd just switch these teams), Alabama beats Texas A&M in the SEC Championship game (I have Texas losing at A&M), and SMU beats Miami in the ACC title game.

The final CFP rankings (or at least the top end of it) end up as follows:

1. Ohio St. (12-1) - Big Ten Champion
2. Oregon (12-1)
3. Penn St. (11-1)
4. Alabama (11-2) - SEC Champion
5. Notre Dame (11-1)
6. BYU (12-1)
7. Indiana (11-1)
8. SMU (12-1) - ACC Champion
9. Colorado (11-2) - Big 12 Champion
10. Georgia (10-2)
11. Ole Miss (10-2)
12. Texas (10-2)
13. Tennessee (10-2)
14. Boise St. (12-1) - MWC Champion

Top 4 playoff seeds would be:
1. Ohio St.
2. Alabama
3. SMU
4. Colorado

First round playoff matchups would be:
5. Oregon
12. Boise St.

6. Penn St.
11. Ole Miss

7. Notre Dame
10. Georgia

8. BYU
9. Indiana

This would put BYU hosting a 1st round playoff game vs. Indiana, with a win putting them in the Rose Bowl vs. Ohio St. I would prefer a Big 12 championship, 13-0 record, and a 1st round bye in the playoffs, but that sort of situation would be a very nice consolation prize.

**I should note that in the above scenario if BYU beats Colorado to go 13-0 and Big 12 champions, I would project them finishing ranked #3 and a 2 seed in the playoffs. They then be waiting to play the winner of Notre Dame v. Georgia in the Fiesta Bowl.