ISedlacek,
we at MUTEC are manufacturing a converter box which is called FORMAT CHANGER multichannel aa. You can have a look at their specs at:
http://www.mutec-net.de/content.php?lng=e&pg=fcmaa
This converter could meet your requirements to convert from AES/EBU or S/PDIF to ADAT lightpipe (or vice versa). Additionally, sampling rate conversion can be added on all channels referenced to external word/super clock or AES/EBU and ADAT. Also bidirectional transfers between both formats are possible. If you need further details, please let me know.
Regards, Christian.
