DD chrono module is not going to happen any time soon, unfortunately. Not really easy task, this module is quite complicated piece of engineering, and DD is quite secretive about all its modules. As far as I have heard, there do not allow (or provide resources for) servicing of modules outside of their manufacture, do not provide spares etc. Allegedly, when servicing ROO chrono movements AP simply replaces module with new one
I think if some of rep movement factories would have necessary resources to do such a complicated reverse-engineering task they would start with ETA 2894 - and manufacture its chrono module. Much more current hot watches use 2894, some already exist as reps with modified 7750, but thickness is always problem, since 2894 is extremely thin for a chrono movement.
regards