As noted earlier, the benefits of status apply only if you're actually going to fly on the airline in question. What's the point in having early boarding and a special phone number for NW (for example) if you're not going to take advantage of them, or will use them maybe twice in the year?

However, if you have some other reason to want status (besides expecting to use it a lot by flying that airline) and charge a lot on credit cards, look into the AmEx Centurion (black) card. The last time I looked it came with mid-tier status on 2-3 U.S. airlines. You don't have to do anything to get the status, other that what you have to do to get the card itself, and you don't use up your one-time shot at getting comped.

There's more on this in the AmEx forum.

BTW, airlines (at least some major ones) are getting pickier about comps. When AA comped me in 1998, they'd match any Delta status except top-tier. By a couple of years ago DL didn't usually do the trick but they'd match United. The latest reports are that they no longer do that automatically either, but that's not yet fully confirmed. More on this in the AA forum, too.