No-one at Apple Computer Inc high enough up to be in the know could be found yesterday to comment on the suggestion from an authorititive source close to the company that among the many projects that have gone onto the back burner in the bottom-to-top shake-up of the company is at least the initial PowerPC-based Macintosh, which had been set for late this year or early next: if the thing has been junked, the reason would likely be that the machine would only fit into the mid-range of the Macintosh line, a slot perfectly well filled by 68030-based machines; there is no reason for Apple to rush to PowerPC, because the 68060 is on the way from Motorola Inc, and with faster versions of the 68040 could keep Mac users happy for years.