A mobile base is listed as an accessory for the 9860zx but I'll double check.
I considered the jet and grizzly combos but both had some downsides. I visited the Felder showroom in sacramento to look at the hammer and 531 jointer/planers and came away thinking that, for a combo, the 531 was the way to go. It is beautifully made and can be placed almost against a wall since the fence doesn't require extra space when at the extreme. The hammer tables tilt when raised and almost double the footprint of the machine. Unfortunately, felder does not have any helical cutter heads. In addition, by the time you add in the accessories for a 531, you're looking at well over $6000 for a machine that is less convenient than separates. (I've used an inca combo machine for 25 years and have adjusted my workflow as such. There were many times, however, that losing the planer setup when going to the jointer was a real pain.) For anyone considering a combo, I would say if you can afford the space, use separates.