Simplepie is a nice little program to use it all one needs to do is create the page layout around the php calls. All the fields that are needed are exposed in the PHP file (for the display or view url) that gets called directly). SimplePie maintains a data cache and you set how often the rss feeds need to be called or refreshed. The system resources that are needed are light, the system only needs to run PHP code and write data files to a directory.
SimplePie Aggregate Theme