THe passenger side can be remounted farther back by drilling new mounting holes in the floor, but the drivers seat has that structural piece up front it has to attach to. WHen we upgrade the seats and have to make/buy an adapter to bolt them in it is easy to move it back, but not so easy with stock seats.
I have made some fine extension-brackets for the drivers seat in my 2005 Jimny. I'm 2 meters tall and really needed some space for the legs. When brackets are mounted, in the original holes, the tracks under the seat, are moved 70mm's to the rear = That's enhancing the comfort for the driver sooooo much - it's really like a limousine !!
They are made of solid steel, painted with a primer, finished in highgloss black. Both the front brackets are supplied with a screw in the extra pin-hole (like the original brackets), to secure that the seat is not "twisted" in an accident.
If anyone would like to buy a set of 4 brackets, incl. 4 new/extra screws for mounting, I would be happy to make a set for you. Mail me for information.