Couple of quick comments.
Inside Freescale and in training we do etc, we typically use MCU to reference a part with internal flash and sometimes it may have a small external bus. We typically use MPU to reference an embedded processor with integrated peripherals and these would include small and large external buses, such as SDRAM, ethernet, PCI, etc...
The industry really doesn't have a clear definition of these two spaces. In ColdFire our MCU family is typically our V1 and V2 cores. The V2 core does have some MCU/MPU hybrids and then our V3 and V4 core based products are MPUs. Many trade magazines and press releases across the industry often use the term "microcontrollers" to cover both MCU and MPU.
In regard to the question on ethernet and USB in an MCU. Is is our policy to not announce or confirm future parts on public forums. But I can tell you this is a very real concept (ethernet and USB) in the MCU market space. And Freescale is always evaluating our customer needs when defining the next generations of our MCU/MPU families.
So all I can say is that we have more and more MCUs coming all the time. If you'd like to see something specific, please post to the forums and request features and functions. The moderators will pass on the information.
Hope this helps.