I want to create a floating shelf for my kitchen but not sure if this is actually do-able

https://ibb.co/8gNqgSKR

so, I want to create a sliding shelf system

ideally, in its stationary state (ie when its near the roof and not taking up any walking around space), its only 27 inches tall so that its not low enough to get in the way of me
and when I need it, I can I pull it down to access stuff on it. the lowest I can pull it without it getting in the way of anything is 63 inches from the roof. but I doubt I would ever need to pull it that low, just wanted to make it clear the range I have the potential for.

it can be a max of 20 inches wide without getting in the way of either cabinet door on either side.

the kitchen is too small for me to allow it to rest on the ground and since I live in a rental, I don't want to drill into the wall and am instead looking to anchor it to piece of wood that would be resting on top of the cabinets on either side.
the piece of wood (or multiple pieces of wood, I don't know what is best) can be 4 inches wide by 11 inches high and the space above the cabinets can provide for 10 inches of depth for the wood to rest on.

is what I am envisioning possible?

I assume I have to custom make this myself and cant order something like this from a store?