First, you are really limiting the search by doing so. Might miss a gem.
Second, most with P5 experience AND available might not be desirable. "Retreads" as some call them.
Third, if they are coveted by others, they will be pricey (big salary, plus buyout if under contract). Not sure we can do "pricey" while shelling out 8.75 million to Fuente (Ouch! Yuge blunder).

The best college coaches of this era are Saban and Meyer. Both were HC's in the MAC at one time. Just sayin'.