What about SLI or CrossFire on Macs?

In the PC world, the current strategy is to develop multiple GPU-based machines. nVidia has been initiating it with its SLI, ATI followed with its CrossFire system. The last high-end Dell computer we were talking about yesterday is an example of those multiple graphic cards-based machines.
We will not comment regarding the real benefit of having multiple GPUs especially if it is only for games; but rather consider that it would be of great help to boost Core video in order to get the best out of the GPUs to generate special effects as well as 3D rendering.
Currently, both GPU giants, for intellectual properties issues, do not allow third parties to develop multiple GPU systems (no licensing currently possible). nVidia is leading this race, and intend to keep it under control by maintaining it compatible only with its nForce chipset, while ATI manufactures itself CrossFire cards, but compatible with Intel chipset solutions.
In summary, if Apple decides to propose multiple GPU machines, it might have to use ATI offers, except if Apple goes one step further into the x86 transition by implementing a non-Intel chipset.
We think that such multiple GPU-based Macs will be available as BTO only with the first PowerMacIntel models, so earliest at the end of the year; and only if Apple can be convinced that such solutions can be of interest for Mac users...if not, for sure some skilled Mac users will try to make it possible.