For those people may know in a similar situation... my searching led me to HDTVs with DVD combos which were smaller. I may have found one that works that does not have a built-in DVD player.
This Naxa 1506 one is small enough it shouldn't be cumbersome, and more importantly has a native HDMI input. I am concerned that it's only 1366x768 and the PS3/PS4 may not be able to natively output that res, so it might need to take 1920x1080 and smoosh it down (causing possibly bad distortion), but it seems to be one of the only ones that fit all the criteria. (Small size, HDMI input, correct aspect ratio.)
I'll ponder it some and see if I really want to do it. It's a small enough investment it's not a big deal, and though the PS3 weighs a ton, I could test it out with that. (Though my unit isn't wireless, so I'd probably have to wipe the system with the current OS info since it's at least 3 years behind, and not update after.)
It's sad to hear laptops don't go both ways. I mean, I guessed that what with equipment all having dedicated in / out ports, and really probably less than 1/4 of 1% of laptop users would want HDMI input, but it's sad there are so few options.