Hey Fellas' (Question, "Real Time Preview" on external (2D) monitor on set)

With Matrox MC-100, we can feed two cameras via SDI and have one HDMI out for Real time preview on external monitor. However Matrox MC-100 is very hard to find now.

I never used AJA Hi5-3D, can any AJA user confirm if we can feed two SDI and have one out for Real Time preview without using any computer?

Also, what other/Updated (cheapest) option do we have for Real time preview on set (since Matrox and AJA both 3D Multiplexer are over 5+ years old? (lol)

Any input will be appreciated.