In the existing vim plugins, none seems to do that.
The only one I've found featuring a clippy box are:
https://github.com/gbigwood/Clippo which allows to show a clippy (in a float?) anywhere with some text, however it's barely configurable and it is written in a python plugin (why not heh)..
NOTE: the clippy in kakoune is really nicely done (using unicode chars!)
Idea from Kakoune editor: https://kakoune.org/
Here I started to write a command, and moving the selection in the completion popup shows the documentation right away in a nice 'clippy' box :)