> I spoke to the general idea of making use of (note: not necessarily "adding," esp.
> where already present) dedicated video hardware and more RAM to a system with
> slow processor to improve performance.

You wrote "dedicated graphics chip", not "dedicated video hardware" (which can be a dedicated chip, a dedicated core inside a SoC or whatever). I advice you to eventually look up what a chip in terms of electronics actually is. So regarding the MPC5121e the usage of a "dedicated graphics chip" (which you subsequently try to turn into the wider concept of "dedicated video hardware") would be equal to adding a second graphics core to the system (one graphics core in the MPC5121e SoC plus one graphics core in the "dedicated graphics chip" makes two graphics cores in the system).
Again it boils down to the question I've already asked you: And now you say that inbetween, i.e. in the 3rd paragraph, you didn't mean to include the MPC5121e when mentioning "slow, low-wattage processor"? Yes or no?

> PowerQuicc is said by Wikipedia to be used in automotive and routers.

We were talking specifically about PowerQUICC II Pro because it's e300 based like the MPC5121e. Automotive is no target application of any PowerQUICC processor (and I doubt it is used in that space either, so I consider Wikipedia wrong in that *) because QUICC is a communications engine:

http://www.freescale.com/quiccengine
http://www.freescale.com/files/graphic/other/NCSG_QUICCENG_VID.wmv
http://en.wikipedia.org/wiki/QUICC (not quite encyclopaedic in its wording)

The MPC8377E I was specifically aiming at has the following target applications according to Freescale: multifunctional printer, small/medium business gateway, IP-PBX systems, network attached storage (NAS), digital media server (DMS).
Admittedly, that may sound like it's hard to build something like a nettop or netbook with it. But technically it has everything you would want for such system, except for (as outlined before) a GPU and AC'97. For these both a dedicated graphics chip (there you go) and a dedicated sound chip connected to the SoC's PCI(e) bus would be needed, or alternatively a combined graphics and sound chip (for instance like the Sam460ex has on-board).

> It's fine with me if someone puts a PowerQuicc processor in a netbook or
> desktop or nettop or smartphone, but I'm not aware that's been done.

Me neither. But that's been the whole point of that part of the discussion: to outline which Power Architecture based processors that are faster than a 400 MHz e300 *could* be used to develop and build such systems.

*) the Wikipedia claim that "Freescale are using PowerQUICC processors as a part of their mobileGT platform" is also false. PowerQUICC and mobileGT (MPC51xx/52xx) do not overlap.