[App_rpt] radio over ip bridging

How would one go about building a node that would bridge echolink, irlp, eQSO, asterisk/app_rpt/allstarlink, skype, etc together in an on demand fashion using a minimum of hardware. I know it can be done using seprate boxes for each and a central controler as glue but what possibilities exist for running these on the same box and simply routing bits between them in software? Note most of the linking protocols mentioned will use gsm as a codec and asterisk can transcode as necessary. Eric