I've heard that AA top tiers get comped for Six Continents (which is otherwise a $100 initial fee). As a UA 1K, I was comped HHonors Gold, and, more recently, Hyatt Diamond (they seem to have gone after top tier flyers who weren't in their program or perhaps didn't stay with them). If you don't want to wait and hope for an invite, why not approach the chain(s) of your choice?