I would just drill N tap some holes in the existing bar, in locations that would be where you may want the stops, and mount them that way.
Jim I was seriously considering to put the x-axis scale in the front just to discover that it won't allow me to use my bed locks. It was all fine up until the point I saw that if I was going to mount the scale cover that it will be totally in the way of the lock levers. Well so now I don't have a choice but to mount at the back. On top of that,remember I said will only be losing about 22mm of travel..........WRONG,with the cover on,it is 40mm,but I think I am going to make a cover that is narrower, it doesn't need to be so wide.Installing with a DRO really creates a conflict because you want to install the DRO scale on the front of the table where the stop would normally go. A lot of people install the DRO scale on the back of the tabel........ Bad idea, this limits your Y travel.