As I recall, someone on here recently with the inside info at AA stated that the new scheduled retirement date is late 2003 for all the 727's. AA has a firm order for some 100+ 738's ,probably of which about half have been delivered. They (AA) did recently pass on some additional future delivery options(about 10??).
My guess is that as the TWA intregration progresses, there is going to be some strategic re-alignment of resources, meaning shifting of more connecting traffic thru STL. The recent 763 order was for 15, thats 6 more than the 9 replacemnts at TW. Rumor has it that there will be a 757 order soon also. I also think that some of the CRJ's will be eventually based from STL, for service on some thinner routes( BOI,FAT for example).
Eventually, you will see hundreds of 738's at AA though.