Yes that feature will be coming right after PyCon! I just have too much to do right now between work, preparing for my talk and getting the next minor release out.
Rye is the only game in town for monorepos atm, but the approach is far from definitive - I believe Armin has acknowledged as much. In particular we’re not completely convinced that the benefits of a single repo-wide interpreter are worth the trade-offs. Very interested to see where you land with it.