Oh, Flipz, that would be awesome!

A scissor-lift that lifts up a candy bucket to receive candy,
and rolls around by itself (I think climbing stairs would be unrealistic, especially because even getting a robot to climb stairs without a load is difficult). Another potential problem would be the scissor-lift itself. In non-LEGO, such as the picture above, pneumatics or hydraulics are used. Because I don't own any LEGO pneumatic pieces, I would need to transfer the rotational energy motion of the motor to linear. Unfortunately, that results in a friction and gear slippage, making me worried that it wouldn't be able to lift a bucket, let alone one with candy. I need to explore my ways of transferring rotational to linear before I consider building.
In the mean time, any other ideas? Just throw them out there. 