Starting from scratch, not taking current conference allignment into consideration.

Based on overall strength of football program, tradition/history, fanbase, TV eyeballs, etc, this would probably be my list:

alabama
clemson
ohio state
oklahoma
notre dame
florida
georgia
michigan
texas
lsu
usc
penn st
miami
washington
tennesee
nebraska
wisconsin
oregon
florida state
auburn
virginia tech
ucla
ole miss
arkansas
texas a&m
kentucky
missouri
iowa
north carolina
south carolina
virginia
pittsburgh
ok state
stanford
mississippi st
northwestern
indiana
michigan st
colorado
west virginia
maryland
byu
cal
asu
louisville
purdue
minnesota
boston college

For BYU to be included, it means they get in over the following P5 programs:

georgia tech
illinois
nc state
duke
syracuse
baylor
tcu
texas tech
kansas st
utah
iowa state
arizona
washington st
oregon st
rutgers
kansas
wake forest
vanderbilt

and all the other G5 programs, including:

cincinatti
houston
memphis
ucf
smu
boise state
usf
san diego state
colorado state
rice
tulane
connecticut
fresno state
unlv
army
navy
air force

Probably would be a long shot for BYU to be included.