> Would it ever be possible to load a version of Android onto one of these phones with enough effort?
Almost certainly not, and if you did it'd be practically unusable. The highest-end Sidekick devices had 128 MB of RAM; the first Android phones, like the HTC Dream, had 192 MB or more. It'd also have no network connectivity, as the Sidekick was a 2G / 3G device and didn't support 802.11 wireless.