Your only real option for upgrades is accruing with the program of the carrier you intend to fly. And the upgrades won't be status-based, you'll have to redeem miles (after you earn them of course!). I don't think anyone other than AA even gives systemwide upgrade certs. And I'm not sure what carriers, if any, allow waitlisting for upgrades, which means status doesn't even help in prioritization, it would be first-come-first-served.

You may also find it harder to earn status on some of these programs, particularly if you're not buying first/business class fares (maybe premium economy).