I am looking for a small field monitor, something big like an iPhone 5 or so, with HD-SDI input and possibly hystograms. It seems that the smaller size around is Lilliput. Anything smaller?

Browse B&H but be forewarned field monitors are very expensive for what you get compared to a smart phone. SmallHD brand is nice if you can afford them.

I own a 7" lilliput but I wouldn't want anything smaller than that. Note the size is deceiving its a diagonal including a large frame. The screen real estate is often substantially smaller than the monitor.

I'm happy enough with my SWIT 7 inchers.

Ron