I've got some live TV shoots coming up where I need up to 128-channels of record channels available.  We're using an SSL L550 console (that's what FOH team uses) taking MADI out to Avid MADI interfaces into a ProTools session, all video sync/locked following 29.94DF TC. 

We have been using multiple JoeCo BlackBox MADI recorders as backups for a couple of years, but have had issues where one or both would drop out of record for no reason.  I'm looking for another option and am SERIOUSLY looking at the MADIface USB as our backup, feeding a backup ProTools session from the SSL MADI to MacBook Pro, and using a CB Electronics TC-5 http://www.colinbroad.com/cbsoft/tc-5/tc-5.html which takes video sync and timecode, converting to MIDI TC that any DAW can sync to (hopefully), allowing the MBPro session to chase to TC.

If we get to an issue of needing more than 64-channels of IO, has ANYONE dealt with issues on USB-2 where you're crapping out using Audio/MIDI manager and doing that many channels over USB?  I do have a MBPro and have confirmed that there are, what looks like, 3 separate USB-C busses.  Making an aggregate device with multiple USB devices is fine to do... just look for bandwidth hiccups.

Any other opinions?

THANKS!!