Well, the video Xen linked to might do the trick – you could stick any number of minecarts on a gigantic monorail engine and just let it shuffle off to its destination. Mind you, I dunno how much work it'd be to create such a beast...
edit: actually, from the looks of things it seems like the only hard part would be building the engine itself, as the track seems to be just a row (with no corners) of redstone torches and (in an optimised version) some repeaters/delays.
EDITED: 4 Jul 2011 08:55 by CAER