The Linux BIOS projects seeks to put a small Linux image into a ROM to manage PC type hardware.
Many have developed "boot from thumbdrive" operating systems, which put the whole OS into a few hundred megabytes, similar to a "Live CD".
Xensource has a developed bare metal hypervisors, including one which targets Windows-only environments. I assume these use a locked-down Linux or BSD kernel to provide the Xen "Domain 0" function. Xensource also provides a Xen Live CD for evaluation.
Meanwhile, as virtualization like Xen and VMware continue to mature, as CPUs evolve to support virtualization (Intel VT, AMD-V), and PCI Express I/O virtualization coming soon, x86 virtualization will become more robust and approach native performance. It is likely virtualized x86 servers will become the norm for production environments.
What would happen if the Linux BIOS, boot from flash memory, and a bare-metal Xen Live CD ideas merged? Imagine a "XenBIOS" project, using a few hundred megabytes of flash memory to hold a live image on board. It would mean virtualization sedimenting into hardware, not into operating systems, as most are currently predicting.
The effect of free, hardware based virtualization which is automatically there would make for very interesting x86 servers. Even more so with a few on-board, fully virtualized, multi-fabric I/O channels. Kind a baby mainframe.
Maybe it's a crazy idea. Maybe its a vision of the future of computing.