(Note that I am no involved in product development (except for the occasional testing of prototypes) and am not authorized to speak about unreleased products.)
A laser add-on for the Shapeoko 5 Pro by an approved vendor is in development — no idea on release date, check in with the folks in Sales for further information.
Some folks have done rotary axes, and it’s possible to do add-ons which translate for example Y-axis movement into rotation. While it’s easy to say “4th axis”, it complicates CAM and work–holding a lot, and imposes rather severe limits on stock size (diameter).
Most of our customers find that two-sided “flip” jobs work well, and there is at least one prototype for four-sided work:
and there are various other techniques — what sort of work do you believe would benefit from this sort of thing?