I don’t see any reason why this wouldn’t work. It is not really a lowrider anymore, since you are dropping the defining characteristic of the gantry raising/lowering.
For a laser that has no mechanical load, you could do something like Rolling Plotter build
or
LowRider-inspired Foam Ripper
For a router that rides on the workpiece like a Maslow, I’m sure there are ways to achieve that. Maybe it could end up like a router sled that is driven in X and Y.