git submodule using worktrees?

I have a number of fairly large projects I work with, for that reason I have a bare clone for each and fork off worktrees as needed in order to avoid unnecessary duplication and pulls between them. That works just fine.

However when I tried to use submodules to provide a unified view of some of those projects I found out that there's seemingly no way to have submodules created as worktrees (off of a shared repository), at least not built-in. It seems like the submodules do set up some sort of bare repository / worktree situation but do not support passing in an existing repository to worktree off of.

`--reference` with `--dissociate` does avoid unnecessary fetches on the initial clone, but they do duplicate objects (and without `--dissociate` has all the issues of a non-static shared alternate), and do require duplicate fetches afterwards to update the submodules, even if the central local repository already has everything.

Q1: is there any way to massage the submodules into working off of a 
central shared repository? Poking around and messing with `.git/modules` 
didn't really work out but I may have just not poked the right bit, 
having to set up the submodules by hand (or via a bespoke script) is no 
issue.

Q2: is there any chance submodules will gain more first-class support 
for worktree-ing off of a local repository in the future