Depends on how you define Mobile and Factory. The Wolf Dragon's brought the jump capable Hephaestus Station with them. There are standard templates for industrial stations and a 0.1g station keeping drive is pretty good to zip around a solar system with so you can adjust your position and find new claims.
Additionally some of the larger dropships could have factory type setups (whether they be actual factories, refineries, smelters, lumbermills, etc..) built into them, I go into this in my Free Trader's guide, link in sig below, although the space required will require the Industrial Tycoon's Handbook fan rules or GM/Author fiat. Smaller dropships could be capable of smelting asteroids into ingots or refining hydrocarbons into useful chemicals as well just not to the same volume.
If you are looking Spice Miner style again there's rules for mobile structures/blue water ships (a fishery ship for instance) and you can look at the Tycoon's handbook for an idea of how big a structure you'd need to make for a purpose.
All of these would probably still be less economical (if not ruinously expensive) than dedicated fixed facilities but they have they benefit of being flexible.
