One of the things AMD is working on are external R600-based graphics card, including versions with CrossFire support:
While this is mostly aimed at desktops, with the PCIe x16 bus-card that will be installed inside desktop PCs, it will also be compatible with upcoming notebooks that feature x16 and x8 connectors. This will bring high-end graphics power to the notebooks for the first time. We already know of one notebook manufacturer that plans to bring external PCIe standard to the world of mobile devices, so it might be possible to have a nice and compact notebook that turns into a gaming rig that can power 24- or 30-inch LCDs.
And this is not all ATI is making external. The company has also done some work on an external Crossfire configuration, although currently most resources are going into getting both the R600 and RV610/630 series out the door during March and April. External CrossFire will come to market probably before summer, oriented towards competing with Quadro Plex. It's not hard to imagine that the GPGPU world is soon going to become a real source of revenue for the company, just like Quadro SDI is for Nvidia.