You can buy new ones, I just did mine and the few that were rusted out were just rusted out around the rubber bushing. Since the sides and most of the top was good I just cleaned them, cut a piece of steel the shape of the top and welded them on. I them drilled out the correct size hole with a cutter I got from Home Depot that fits to a normal drill. It worked out very well. Much easier then cutting off the old ones and putting new ones on. I could have done a much cleaner job, but it is under the jeep! I am sure they are as solid as the original as I only really had to patch the area for the bushing. I had to do the for in the rear and 3 others.
I have attached a picture of one of them. Not great but you can see it.
I also attached a picture of removing the body with an engine hoist connecting it to the seatbelts. Just locked them in on each side and hooked the two belts on. Allowed me to slowly lift it and check everything, and made putting it back on very easy as we could slowly lower it line it up etc. Worked better then I could have hoped. I had my son help me but with this approach and being able to roll it I would not hesitate to do it by my self, and it was fairly balanced, could roll with one hand and steady with the other. It was also very solid. I tested a lot before I finally decided to really lift it off the frame.