Has anyone seen a tablet style tv?

I've been looking for a 7-10 inch tv with hdmi, vga, and rca inputs that has an internal battery. possibly an audio out for the hdmi if there are no speakers, although it isn't a big deal. I've been looking and can't seem to find them.

This seems odd since no tablets seem to have hdmi-in, only hdmi-out. I have seen hdmi out, tablets for under a hundred dollars, yet what I want is basically a tablet without the cpu, wireless capabilities, and internal storage. how can that be such a complicated device to build?

The reason I want one is my camera can output live view through hdmi, and modern cameras no longer seem to have focusing aids anymore for manual lenses like the ones in my camera bag or the much better ones my grandfather has with his Minolta. without the split prism and split image aids fine tuning the focus on far away subjects is very, especially when they are carnivores staring at me. I don't want to get closer to then necessary, and I want my photos to be clear. A larger screen coupled with the ability to digitally zoom in the frame in live view would be greatly helpful though a sad replacement for the focus technology we had in the 1980's

so has anyone ever seen what I'm looking for?