The latest rumors on Usenet concerning the next generation Macintosh CPU have been leaning toward the 68040. Some time ago, MacWEEK reported that Apple was looking to the Motorola 88000 series of RISC chips to power the next Macintoshes. However, such a machine would not be Macintosh-compatible without emulation software that would waste the power of the 88000 chip. Such a machine might be in the works, but won't be coming within the next year.
The 68040 does seem more likely considering that it would provide compatibility with current Mac software. In fact, some people said that Apple has a 68040 machine designed and is only waiting for Motorola to step up production of the 68040 chip to make the manufacturing process economically feasible. We hope Apple is using the time to reduce any problems with software incompatibility.