Current Status:

Now the iPad has (very decent) mouse support, it may actually be viable to properly work with an external display. I’ve hooked mine up to a 4k monitor in the past, but not only did the screen look far worse than that on the iPad already, having to touch the screen limited what you could do a great deal.

I’ll have a play around with it over the weekend see just how viable it could be for certain tasks. It’s a shame you can’t turn the iPad display off when hooked up to an external monitor, however.