New hardware?

[MBTC]

I personally think CPU technology has hit a ceiling (actually its been hovering around the ceiling for many years now). They are adding more cores, which is good for certain types of applications, but as has been discussed here before some computing tasks are serial in nature and do not lend themselves completely to parallelism. Thermal limitations, among other things, prevent CPUs from getting much faster.

GPUs on the other hand still seem to be enjoying big performance gains, generation over generation, while finding ways to do so with lower temperatures and less power consumption. Exciting times in GPU-land, not so much on the CPU side of things.

All of that aside for a moment, and taking into consideration what you've brought up about Apple's diminished focus on desktops: Lots of the buyers of Apple computers for music making purposes go with laptops or iMacs, partially for value but more likely for mobility. DJs and musicians are on the go more than ever. That presents a problem for makers of, for example a DSP card like the TC Powercore since there's no where to put the card. What's more, high-end GPUs need a desktop as well for thermal reasons, better airflow is required. You mentioned the possibility of an external box, but then you we the benefit of a bus directly on the motherboard, and its back to the streaming over USB/Firewire etc. Of course, this can be done, but we've seen it can be flaky and come with drawbacks of its own like latency.

Did you ever look at the Openlabs stuff? They still sell the Meko, although I can't say I know of anyone that uses one. It's kind of like what you've described, a separate box (just happens to have a keyboard) with its own DSP... well actually better than a DSP -- rather a full blown PC running Windows and lots of soft synths http://openlabs.com/LxdPage