Family Travel Rewards

This past weekend caused me to think again about Frequent Flyer, or loyalty rewards program. I fly a lot, enough to maintain a high level status on at least one airline a year, right now it's Delta, and have roughly 300,000 miles lifetime on three different airlines, so I get some perks. The problem is my wife doesn't fly as much, and tends to fly different airlines for work than I do, primarily due to locations we travel to. So we end up in a situation where one person gets upgraded and the other doesn't quite frequently, or if we're on a different itinerary, unable to sit next to each other due to how the pricing works. Now we could fly Southwest, but no matter how many advertisements Southwests has saying how great it is for business travelers, my own experience tells me otherwise, so that's not an option.
  This led me to think, why isn't there a family plan? You can even make it harder, double the requirement and add 10% per person to make it a real debate, and then make the points non-transferable to an individual account? Since the airlines are fairly standard, see below for a rough layout of my thoughts.

Level	Individual Miles	Joint Mileage
Silver	25,000	60,000
Gold	50,000	115,000
Platinum	75,000	170,000

   So as you can see, I didn't make the relationship strictly a multiplier of 2x on the existing structure to force it to be a real decision. While the current system is extensible to another person on the same ticket, you also end up having two accounts with an enormous amount of miles, but need to combine them for rewards, which is just a pain for you and the agent you talk to, unnecessarily so. It also requires a significant amount of travel to make a level, so in the majority of places one person will not be able to carry the entire family account.

The next thought was if you wanted to make a third person active, the amounts would increase again by the same method used here, ie 2*(base)*#ppl+10,000+5,000*(base level).

This was just a thought I had, so what are yours? Airlines get on it!