Get a Black and Decker WorkMate, Ive got 3 kicking around here. Two 200's and a 400. (Older Mod. No's. so new might be different).
They all have 3 work heights, well technically 4. folded flat you can use them at near ground level, about 6" or so. They have short extension legs that can swing out and provide maybe 6" of lift, and a wider stance.
Then you can extend them to the "normal" work height, and use them with or without the extendable legs. I use the different work heights all the time depending on what I'm doing.
The 200's have the basic sliding jaws, but the static jaw can be slotted in several positions for more capacity.
The 400 will do all the above, plus you can unlock the dynamic jaw and swing it up 90 degrees to a vertical position, and clamp downwards onto the static jaw. A handy feature I have used any number of times.
All come with the bench dogs, so you can lay a board on top and clamp it, or just use the jaws like a vise.
Once you have one, since they are VERY stable, you can mount up bench tools like grinders, arbor presses, even small to mid size machinist vises, onto a wood base and add a bar on the bottom to clamp onto and have whatever workstation you need and place it where ever you need it. I add a "safety plate" to the clamping bar (that bar has to be a little thicker that the WorkMate's jaws) so if it happens to vibrate loose it does not come out.
I don't think you could get away with that on the lighter "TV tray" designs.
Lastly, I rack a number of mounted tools into a 2 ft wide shelving unit that has adjustable shelf standards, and the mounting plate is cut to the correct width to allow it to become the shelf. this makes it so the clamp block on the bottom doesn't rock as it would if it were sitting on a shelf.
Here is a shot of a plate waiting for my next tool:
