The cross-platform solutions is ipmidi (commercial windows/osx and open source linux qmidinet) and jackaudio (IP open platform).
Despite this (=IP stack overhead), ipmidi achieves excellent performance results (with a gigabit ethernet card one-way direction latency is 0.07ms and jitter is <0.2ms between linux and windows).
I would like to try a pre-release version of ALSA linux CopperLAN... or a FreeRTOS solution...or a hardware solution...or an embedded solution...to make the measurements.
Thanks
Elia