I have never converted a reel to video cabinet, but I once tried to go the other way around. These are the issues I found out, which basically made me just get a another reel machine.
1. The amp board on the reel machine is connected to the reel controller backplane, so I'm guessing you would have to leave that there for the amp to get juice and signal.
2. I couldn't mount the reel controller as I had no hardware, I suppose you could just remove it from the machine as I'm not sure if it would interfere with the monitor's depth in that area.
3. There were other misc harnesses that were different, again, mostly requirements for the reels, so I think you would be OK going the other way around.