I have completed fabrication of the TV "flag" lift. Came out really well, but it was a lot more subtle than it looked. Here is a video:
The whole thing is only 2.5" thick, which I am pretty proud of (the best commercial equivalent I found was twice as thick, and required 120VAC). This is important since it steals space from under-counter storage. The thinness came mostly from (a) using a computer monitor rather than a TV; and (b) careful arrangement of the mechanism. The complex shape at the bottom has to do with fitting it around the wheel well.
The unpainted wood piece at the top is a placeholder for a hatch made of countertop material. The unit is controlled from a wall-mounted up/down switch (two momentary-contact switches). The hatch is opened and closed automatically, using a separate, tiny 2" actuator, and the tv is powered on or off as appropriate. The inside of the TV box is lined with felt, so the TV screen is protected. It stores tightly, so no rattle.
There were a number of tricky parts:
1) My first attempt depended only on the linear actuator to hold the TV. What I didn't realize is that these guys are not designed for any lateral torque. Even though the monitor is only six pounds, the off-center load produced a LOT of torque. Version two added a drawer slide behind the actuator to absorb the lateral forces. Version three moved this slide to be next to the actuator, rather than behind it, in order to save thickness.
2) The hatch open/close mechanism was a little tricky, due mostly to my inexperience with such things. I ended up mounting the actuator at the bottom using a long, stiff screen-door spring as a linkage. Works really well and the springiness pulls the hatch tight when it is closed, so it won't vibrate.
3) I had to take care making everything serviceable from the front, making sure that no screws from the back had to be removable.
4) The hardest part involved sensing the angle of the "flag". This had to be done with some precision, since it is needed to prevent any attempt to close the TV when it isn't aligned with the slot. First I tried a hall-sensor and a magnet. Couldn't get enough precision. Second, I tried an optical sensor mounted at the pivot. Couldn't get that to work, either. Finally, I got a little laser reflective sensor. It is mounted at the bottom of the box and points upward toward the bottom of the TV, which has a patch of prismatic reflective tape. When you press the "down" button, a red light goes on inside the slot until the TV is moved over the slot, at which point it turns green (which you can see in the video) and the tv starts moving downward.
This project is a great example of the usefulness of ESPhome. I built a custom module (in the box near the bottom with the red lights) which controls the actuator motor controller, reads the laser sensor and position feedback from the actuator, reads the up/down button inputs, controls the red/green LEDS and properly sequences the various actions. There was a lot of subtlety getting it to work seamlessly. I don't know how I would have done it otherwise. As an extra bonus, it automatically appears in Home Assistant, so it can be controlled and automated from the touch panel. Very slick. Can't wait to see it installed in the van.