Not sure where you located but try taking it to a machine shop and get them to quote cutting it, threading both halves(left hand, right hand threads) and coupling it with something like this Moog part(or a solid steel one with lock nuts). It depends on how much extension you need of course... This method may yield a couple inches at most.
I used to do these all the time for a local suspension shop and they would take me 40 min to an hour at most. The shop just needs a big enough lathe to fit the rod ends through the headstock. My 80 came with extended panhard bar from Japan with a butcher job of pipe welded over bar, threaded rod and a nut. I probably should remake it at some point.