With the current state of being limited to AMD/ATI GFX that would exclude all MacMinsi and all but the bigger Pro MacBooks, so that a hard pass.

The last glimpse of MorphOS-AMD64 we got (at Amiga34) was running on a at that time current mobo with an ancient RadeonHD card and AFAIK adapting it to different mobos wouldn't be that big of a problem (for basic functionality).

In the long run it would IMO be best to focus on AMD CPUs with integrated GFX as that seems to be the only viable way to supporting a laptop or small form factor desktop (pretty much everything else is either Intel with integrated GPU or NVidia).