Ken,
What don't you like about either of my suggestions? There shall be no "premeditated wagering agreements" between players, prior to any deal. Or; Premeditated wagering agreements prior to any deal, are strictly prohibited and subject to penalty and possible disqualification from play.
It is impossible to police all situations. However, when the situation is as obvious as the original post, player's should not be allowed to go all-in blind without penalty. If they are warned, or penalized effectively they should stop, don't you think? I also don't agree that it is the same as a player betting in the dark.
Years ago, we used to play a game called "showdown." We would agree before the deal as to how much we would all risk. The amount was placed into the pot equally, by all players. The dealer would proceed to deal five cards (face-up) to each player...slowly, and one at a time. At the end, the player with the best poker hand won. That was fine for a cash, house game.