Humans have filled an evolutionary niche as a relatively-long-lived, highly intelligent, social, tool-using species. Our bauplan has little to do with this other than the fact we have fine dexterity in our hands, and big brains. However, lots of animals can manipulate objects roughly as well as apes (e.g. parrots, octopi), so all you need for the rest is a social species and a large, densely-connected brain and decent lifespan. The social aspect is important because without a way for information to be disseminated, abstract concepts would be too difficult for every lone creature to grasp independently. And without a long enough lifespan for the learning to take place, any kind of "societal progress" likely won't arise. Thank heaven octopi don't live very long!
Remember: The main reason most chordates on Earth have a central nervous system is that they all share a common ancestral species, not necessarily because that's the best or only setup that gives rise to high intelligence. But there's no reason life on an alien planet should have to evolve the same way (though a bipedal upright gait is much more efficient than quadrupedal). If you want to get creative with your longer-than-it-is-tall species, nothing is stopping it from having an elongated brain instead of a round one. In such a creature, maybe the brain runs along the spinal column in a protected area, like a shell. This avoids a heavier head, though as other users have pointed out, the weight isn't particularly bad for other mammals here on Earth, anyway.