Hi There,

I would like to know if there are any device that can remotely trigger the shutter release for 50 units of EOS DSLRs (5DmkII) simultaneously. Thanks!

Depending on the range you need. Here is one example. What you would do is have a single transmitter and 50 receivers for that frequency.

Zeikos RC-6 Wireless Shutter Release Remote Control for Canon Digital SLR Cameras for Rebel XT, XTi, XSi, T1i, T2i, T3i & EOS 60D, 7D