In short, it doesn't look likely without some extreme hacking that nobody has done.
Microsoft have deliberately nobbled the Windows 8 specification so that this can't happen on ARM-based machines.
To be Windows 8 RT compatible (ARM machines only) it must not be possible to disable or reconfigure secure boot. So if you have an ARM machine that can run Windows 8 RT then it can only run an operating system signed by Microsoft.
So the Surface RT is like all other Windows 8 RT in that it's very much a device for muggles and mouse mittens; no Linux or BSD wizardry allowed, no dual-booting hacked-up iOS and no Android either. I can understand why they'd do this because most people are pointers and clickers, but it's not a machine for tech-heads.
The Surface Pro has an Intel i5 machine so hopefully Ubuntu 13.04 will support it of the box, if it does then I'll get one.
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