SUPPOSEDLY, someone at Glocktalk spoke to a rep from Glock Inc and they will replace cracked mag bodies now. He said that as long as Glock can prove that they didn't do anything to increase the total number of hicap mags, it is okay by the BATF.
However, he was the only one so far that has had this done for him by Glock Inc. Go for it and tell us if they did!