I don't think there is a "force them to play or pay" scenario that works. If you try to force a 1st round draft pick to play, at any time during the season, they can either play half-assed, fake injury, or violate an NCAA rule. The player's agent can explain to the NFL scouts what is going on, and would front the money for a financial penalty that might be assessed against the player by the school.
I also can't see the "breach of contract" penalty working, as recruiting already puts all of the power in the player's hands. It would simply become another bargaining chip: "Ohio State isn't going to have a financial penalty for leaving early in their commitment contract, but Florida is. Hmmm, I think I'll go to Ohio State".
As fans I think we need to reset our expectations that likely 1st round picks are going to skip their bowl games, and be pleasantly surprised when a few don't. I don't like it, but the stakes are simply too high to expect a top-talent facing a multi-million dollar payoff for years of hard work to risk it all.